to happen suddenly.

Severe thunderstorms flare up there at almost any time during the summer.

You may not feel like chopping vegetables when the pain in your hands flares up.

Etymology: based on the literal meaning of flare up (= to suddenly burn brightly)

• If thinks something, they've got another think coming!
• If thinks, they've got another thing coming!
• If thinks, they've got another think coming!
• if worst comes to worst
• If you believe that, you'll believe anything!
• if you can help it
• If you can't beat 'em!
• If you can't beat 'em, join 'em!
• If you can't stand the heat, get out of the kitchen.
• if you catch my drift
• if you get my drift
• If you pay peanuts, you get monkeys.
• if you play cards right
• if you play your cards right
• If you've got it, flaunt it!
• Ignorance is bliss.
• I guess so
• I have to hand it to
• I have to hand it to someone
• ill at ease
• I'll be a monkey's uncle!
• I'll be damned
• I'll be damned if I
• I'll be damned if I do something
• I'll believe it when I see it.