give a heads up
- alertWarning or watchfulness
- warnGive notice of peril
- notifyFormally communicate information
- tip offSecretly inform beforehand
- signalMessage-conveying cue
caution · inform · forewarn · clue in · reminder · notice · watch out · briefing · update · flag · ping · message · preparation · courtesy · whisper · insider · nudge · lookout
advance warning vs. concealment
give a heads upkeep secret
Not reveal information
conceal · hide · keep mum · hold back · keep to oneself
preparation vs. surprise
give a heads upblindside
Surprise with unexpected force
catch off guard · ambush · take by surprise · surprise · catch unawares