In his book of tafsir, Imam al-Shawkaani brought the following discussion about the meaning of the term al-Maseeh (the Messiah). Imam al-Shawkaani generally borrowed heavily – even word for word – from Imam al-Qurtubi’s linguistic discussions, often summarizing and simplifying them into a list format. Some supplementary notes from al-Qurtubi will be mentioned here in brackets  for the sake of clarity:
[والمسيح لقب لعيسى ومعناه الصديق ; قاله إبراهيم النخعي . ـ]
[al-Maseeh is a title for ‘Eesaa (Jesus) and its meaning is al-Siddeeq (“the truthful one”) – this is what Ibrahim al-Nakha’ee said.]
والمسيح اختلف فيه مماذا أخذ ؟ فقيل : من المسح ; لأنه مسح الأرض ; أي : ذهب فيها فلم يستكن بكن ، وقيل : إنه كان لا يمسح ذا عاهة إلا برئ ، فسمي مسيحا ، فهو على هذين فعيل بمعنى فاعل ، ـ
al-Maseeh – there is differing as to where it was derived. So it is said: (it was derived) from al-mash (wiping), for he swept over the earth, meaning he traversed over it and did not take residence in any dwelling place.
And it is said: It was the case that he would not touch someone with an infirmity except that they would be cured, so he was called Maseeh.
So according to these two meaning, it takes the form of an adjective with the meaning of an active participle.
وقيل : لأنه كان يمسح بالدهن [البركة] الذي كانت الأنبياء تمسح به [ طيب الرائحة ; فإذا مسح به علم أنه نبي . ] ، وقيل : لأنه كان ممسوح الأخمصين ، وقيل : لأن الجمال مسحه ، وقيل : لأنه مسح بالتطهير من الذنوب ، وهو على هذه الأربعة الأقوال فعيل بمعنى مفعول . ـ
And it is said: (He is called that) because he was anointed with [blessed] oil, as the prophets used to be anointed with that, [having a good scent. So if one was anointed with it, then it was known that he was a prophet].
And it is said: because the soles of his feet were anointed (with ointment).
And it is said:because beauty of his cleanliness.
And it is said: because he was cleansed with purity from sins.
And according to these four meaning, it is an adjective taking the meaning of a passive participle.
وقال أبو الهيثم : المسيح ضد المسيخ بالخاء المعجمة . وقال ابن الأعرابي المسيح الصديق . ـ
And Abu Haytham said: al-Maseeh is the opposite of the obscure word al-maseekh (meaning “misshapen”). And ibn al-‘Arabi said: al-Maseeh means al-Siddeeq (“the truthful one”).
وقال أبو عبيد : أصله بالعبرانية مشيخا بالمعجمتين فعرب كما عرب موشى بموسى . وأما الدجال فسمي مسيحا ; لأنه ممسوح إحدى العينين ، وقيل : لأنه يمسح الأرض أي يطوف بلدانها إلا مكة والمدينة وبيت المقدس . ـ
Abu ‘Ubayd said: It’s root in Hebrew is Masheekh according to the two lexicons, so it was arabized just as Moshe was arabized as Moosaa. As for al-Dajjaal, then he is called maseeh because one of his eyes is rubbed over. And it is said: because he will sweep over the earth, meaning he will tour its lands, except for Mecca, al-Madeenah and Bait al-Maqdis.
[وقد قيل : إن المسيح اسم لعيسى غير مشتق سماه الله به . فعلى هذا يكون عيسى بدلا من المسيح من البدل الذي هو هو . ـ]
[And it has been said that al-Maseeh is a proper name for ‘Eesaa which is not derived from anything; that Allah named him with it. So according to this, the name ‘Eesaa can be substituted for al-Maseeh just as ‘him’ and ‘him’ can substituted for one another.]
[Fath al-Qadeer 1/219, with supplementary notes from Imam al-Qurtubi’s Jaami’ l-Ahkaam al-Qur’an 4/85-86 in brackets]
And Imam al-Baghawi also included a list of several different interpretations, including some which neither Imam al-Qurtubi nor Imam al-Shawkaani mentioned:
واختلفوا في أنه لم سمي مسيحا ، منهم من قال : هو فعيل بمعنى المفعول يعني أنه مسح من الأقذار وطهر من الذنوب ، وقيل : لأنه مسح بالبركة ، وقيل : لأنه خرج من بطن أمه ممسوحا بالدهن ، وقيل مسحه جبريل بجناحه حتى لم يكن للشيطان عليه سبيل ، وقيل : لأنه كان مسيح القدم لا أخمص له ، وسمي الدجال مسيحا لأنه كان ممسوح إحدى العينين ، ـ
And they differed as to why he was called Maseeh. Among them were those who said: it is an adjective with the meaning of a passive participle, meaning that he was wiped clean of any stains and purified of sins.
And it is said that he was wiped with blessing.
And it is said that he exited from his mother’s womb anointed with oil.
And it is said that Jibreel touched him with his wing, since the shaytaan does not have any means against him.
And it is said: because he his feet swept over the earth, leaving no soles for him.
And al-Dajjaal was called maseeh because one of his eyes is wiped over.
وقال بعضهم هو فعيل بمعنى الفاعل ، مثل عليم وعالم قال ابن عباس رضي الله عنهما سمي مسيحا لأنه ما مسح ذا عاهة إلا برأ ، وقيل : سمي بذلك لأنه كان يسيح في الأرض ولا يقيم في مكان ، وعلى هذا القول تكون الميم فيه زائدة وقال إبراهيم النخعي : المسيح الصديق ويكون المسيح بمعنى الكذاب وبه سمي الدجال والحرف من الأضداد ـ
And some of them said that the word is an adjective with the meaning of an active participle, such as ‘aleem and ‘aalim. Ibn ‘Abbaas said, “He was called maseeh because he would not touch someone with an infirmity except that that person was healed.”
And it is said: he was called that because he traversed across the earth and did not settle in any place, and according to this position, the letter meem in it is an addition (i.e. not part of the root).
And Ibrahim al-Nakha’ee said, “al-Maseeh means al-Siddeeq [“the truthful one”], and al-Maseeh can take the meaning of al-Kadhdhaab [“the perpetual liar”], and this is why al-Dajjaal is called this, and this is a word that can take on two opposite meanings.”
[Tafsir al-Baghawi 2/39]
For more on the meaning of the word al-Siddeeq, see: A Point of Benefit regarding Truthfulness: Imam al-Sa’di
See also: Imam al-Shawkani on the Gospels