List of hold out on synonyms and hold out on related words.
bosom, classify, conceal, file and forget, hold back, in petto, keep, keep back, keep between us, keep buttoned up, keep close, keep dark, keep from, keep in ignorance, keep mum, keep secret, keep snug, keep under wraps, make no sign, never let on, not give away, not tell, play dumb, secrete, veil, withhold