very informal!

a rude way of telling someone that you are very angry at something they have just said or done.

A guy started hassling me while I was ordering drinks at the bar, so I told him to drop dead.

• if it ain't broke, don't fix it
• If it ain't broke, don't fix it.
• if it comes to the crunch
• if it weren't for
• if it weren't for someone
• if it weren't for something
• if knows what's good for
• if knows what's good for them
• If looks could kill...
• if memory serves
• If Mohammed will not go to the mountain, the mountain must come to Mohammed.
• if need be
• if push comes to shove
• if someone knows what's good for
• if someone knows what's good for them
• If someone thinks something, they've got another thing coming!
• If someone thinks something, they've got another think coming!
• If someone thinks, they've got another thing coming!
• If someone thinks, they've got another think coming!
• If the cap fits .
• If the cap fits wear it.
• if the going gets rough
• if the going gets tough
• if the worst comes to the worst
• If thinks something, they've got another thing coming!