bad sport
poor sport

Charlie smiled, not wanting to be a bad sport about it.

Naturally the other head didn't appreciate this; giants were bad sports even at the best of times.

Bloody bad sports, those darkies, wouldn't stand still and be shot.

That ole boy's about the worst sport I ever seen.

It was the worst sports team air disaster in history.

That just makes you look like a bad sport.

The terms were in wide use around the company and anyone who objected to being so designated was considered a bad sport.

It's considered bad sport to torture the enemy to death.

The one thing the crowd couldn't call Rosario, however, was a bad sport.