Cheap Shot

What does the idiom “Cheap Shot” mean?

Definition:

An unfair attack; a statement that unfairly attacks someone’s weakness

For example:

“When you criticized Christina for missing work, that was a cheap shot. We all know she’s been taking care of a sick child.”

Notes:

This idiom comes from American football, where a cheap shot is a tackle made on a player who does not see the tackler coming.