Adam Clarke on 1 Timothy 3:8

Likewise must the deacons - The term deacon, διακονος, simply signifies a regular or stated servant: from δια, through or emphatic, and κονεω, to minister or serve. See it explained in the note on Mat 20:26. As nearly the same qualifications were required in the deacons as in the bishops, the reader may consult what is said on the preceding verses.

Grave - Of a sedate and dignified carriage and conduct.

Not double-tongued - Speaking one thing to one person, and another thing to another, on the same subject. This is hypocrisy and deceit. This word might also be translated liars.

Not given to much wine - Neither a drunkard, tippler, nor what is called a jovial companion. All this would be inconsistent with gravity.

Not greedy of filthy lucre - See on 1Tim 3:3 (note).