Answer: ulteriormotive

AnswerCrossword Clue
ULTERIORMOTIVEReason kept to oneself
ULTERIORMOTIVEPart of a hidden agenda: 2 wds.
ULTERIORMOTIVEReason for coyness, maybe
ULTERIORMOTIVEReason that's out of sight?