- WARN
- Caution
- Sound the alarm
- Give a red flag, e.g.
- Alert
- Counsel
- Cry wolf
- Tip off
- Give a heads up to
- Give a caveat
- Use a Bac-a-Larm
- Give a signal
- Notify of peril
- Put on notice
- Say "Better not" to
- Admonish
- Do an oracle's job
- It's useless to do it after the fact
- Issue a caveat to
- Advise caution
- Give notice to
- Clue in
- Say "Watch out!" to
- Give the heads up
- Advise
- Give notice
- Shoot off a flare, e.g.
- Honk at, perhaps
- Say "Be careful" to
- Shout "Fore!" to
- Wave a red flag at
- Say "Watch it" to
- Advise of danger
- Bark or bite
- Threaten
- Put on guard
- Give an alert (to)
- Notify in advance
- Inform of danger
- Advise caution to
- Alert to danger
- Put on alert
- Yellow-card
- Pre-inform.
- Notify
- Cry wolf and mean it
- Sound the tocsin
- Use a tocsin
- Counsel, perhaps
- Raise a red flag
- Give an alert
- Premonish
- Serve notice
- Show a yellow card, e.g.
- Say "It's a trap!," say
- Yellow-card, e.g.
- Not punish just yet
- Try to save, maybe
- Cry 'Heads up!' to
- Foretell consequences
- Issue a foreboding statement
- Raise red flags
- Notify of risk
- Advise (against)
- Alert of danger
- Let off without a ticket, e.g.
- Notify of potential danger
- Cry "Fore!" to, say
- Honk at, say
- Show a red flag to
- Yell "Heads up!" to, say
- Tip off ahead of time
- Alert urgently
- Give the high sign to
- Utter "...or else!"
- Urge caution
