transitive verb
1.
a. : to keep from expressing : hold back
kept his feelings in until he nearly burst
was unable to keep the secret in
b. : to detain in the school after regular school hours as a punishment
kept the children in for disobedience
2. archaic : to keep (a fire) burning
intransitive verb
1. of a fire : to keep burning
2. : to stay on good or favorable terms
anxious to keep in with the boss