wouldn't harm/hurt a fly

if you say that someone wouldn't hurt a fly, you mean that they are a gentle person and that they would not do anything to injure or upset anyone.

Damian just isn't the violent type. He wouldn't hurt a fly.

• a face as long as a wet week
• a fact of life
• a factory farm
• a fag hag
• a fair shake
• a fair-weather friend
• a fairy godmother
• a fait accompli
• a fallen angel
• a fallen idol
• a fallen woman
• a fall from grace
• a fall guy
• a false alarm
• a false dawn
• a false economy
• a false start
• a family man
• a far cry from
• a far cry from something
• a fashion victim
• a fast talker
• a fast track
• a fat cat
• a fate worse than death