Meaning of keep back

(verb) secure and keep for possible future use or application; "The landlord retained the security deposit"; "I reserve the right to disagree"

hold back; refuse to hand over or share; "The father is withholding the allowance until the son cleans his room"

prevent the action or expression of; "hold back your anger"; "keep your cool"; "she struggled to restrain her impatience at the delays"