gaffe or (rare) gaff /gaf/

A blunder

• smash-up
• smash-ups
• smatch
• smatched
• smatches
• smatching
• S-matrix
• smatter
• smattered
• smatterer
• smatterers
• smattering
• smatteringly
• smatterings
• smatters
• smaze
• smazes
• SMD
• SME
• smear
• smear campaign
• smear campaigns
• smear dab
• smear-dab
• smeared