keep back in WordNet English dictionary

1. secure and keep for possible future use or application
   "The landlord retained the security deposit"; "I reserve the right to disagree"
   retain  hold  keep back  hold back 
   
2. keep under control; keep in check
   "suppress a smile"; "Keep your temper"; "keep your cool"
   restrain  keep  keep back  hold back 
   
3. hold back; refuse to hand over or share
   "The father is withholding the allowance until the son cleans his room"
   withhold  keep back