hold out on (?.)

• 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