not injure or upset anyone or anything.

She said the arrest was a mistake, that her husband wouldn't hurt a fly.

Usage notes: also used in the forms can't hurt a fly, couldn't hurt a fly, and would never hurt a fly:

He was so gentle he would never hurt a fly.

• put yourself through something
• put your shirt on
• put your shirt on something
• put your shoulder to the wheel
• put your thinking cap on
• put your two cents in
• put your two cents worth in
• puzzle out
• puzzle out something
• puzzle over
• puzzle over something
• Pyrrhic victory
• QED
• quantum leap
• queer fish
• queer pitch
• queer someone's pitch
• question mark over something
• queue-jump
• queue-jumper
• quicken pulse
• quicken the pulse
• quicken your pulse
• quick-fix
• quick fix