Strong's #3338: metamellomai (pronounced met-am-el'-lom-ahee)
from 3326 and the middle voice of 3199; to care afterwards, i.e. regret:--repent (self).
Thayer's Greek Lexicon:
1) it is a care to one afterwards
1a) it repents one, to repent one' s self
Part of Speech: verb
Relation: from G3326 and the middle voice of G3199
Citing in TDNT: 4:626, 589
This word is used 6 times:
Matthew 21:29: "not: but afterward he repented, and went."
Matthew 21:32: "and ye, when ye had seen it, repented not afterward, that ye might believe him."
Matthew 27:3: "when he saw that he was condemned, repented himself, and brought again the thirty pieces of silver"
2 Corinthians 7:8: "I made you sorry with a letter, I do not repent, though I did repent: for"
2 Corinthians 7:8: "a letter, I do not repent, though I did repent: for I perceive that"
Hebrews 7:21: "swore and will not repent, Thou art a priest forever"