(un-) accustomer, -ing) X diligently, expert, instruct, learn, skilful, teach(-er,

Concise Bible Dictionary:

The “teacher” is one of the gifts set in the church (1 Cor. 12:2828And God hath set some in the church, first apostles, secondarily prophets, thirdly teachers, after that miracles, then gifts of healings, helps, governments, diversities of tongues. (1 Corinthians 12:28); Eph. 4:1111And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; (Ephesians 4:11)); and the teacher is exhorted to be occupied with teaching (Rom. 12:77Or ministry, let us wait on our ministering: or he that teacheth, on teaching; (Romans 12:7)). “Teaching” is the intelligent setting forth of the truth by the Holy Spirit, and this does not leave room for the mind and opinion of man. Paul left Timothy at Ephesus to charge some not to teach other doctrine than what the apostles taught; and those that did teach otherwise are said to be “puffed up, knowing nothing” (1 Tim. 1:33As I besought thee to abide still at Ephesus, when I went into Macedonia, that thou mightest charge some that they teach no other doctrine, (1 Timothy 1:3); 1 Tim. 6:3-43If any man teach otherwise, and consent not to wholesome words, even the words of our Lord Jesus Christ, and to the doctrine which is according to godliness; 4He is proud, knowing nothing, but doting about questions and strifes of words, whereof cometh envy, strife, railings, evil surmisings, (1 Timothy 6:3‑4)). This makes evident that no other teaching could be of God; hence the modern formula of “agreeing to differ” on vital points of doctrine is not recognized. On the contrary, the apostle said, “I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment” (1 Cor. 1:1010Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. (1 Corinthians 1:10)).
A caution is given in James 3:11My brethren, be not many masters, knowing that we shall receive the greater condemnation. (James 3:1), “Be not many teachers,” for it involved greater responsibility. The same word (διδάσκαλος) occurs in John 13:1313Ye call me Master and Lord: and ye say well; for so I am. (John 13:13), where the Lord owned Himself to be the Teacher, and He was many times addressed as “Teacher”; though in nearly all cases the AV has “Master.” He taught as one having authority, and not as the scribes.

Strong’s Dictionary of Hebrew Words:

Number:
3925 (find all occurrences in KJV Bible)
Transliteration:
lamad
Phonic:
law-mad’
Meaning:
a primitive root; properly, to goad, i.e. (by implication) to teach (the rod being an Oriental incentive)
KJV Usage:
(un-) accustomed, X diligently, expert, instruct, learn, skilful, teach(-er, - ing)