Foul-tempered is a term used to describe someone who has a bad temper and is often irritable or angry. The two crossword solutions for this term are GRUMPY (6 letters) and SURLY (5 letters). GRUMPY is an adjective used to describe someone who is easily annoyed, irritable, and bad-tempered. SURLY is an adjective used to describe someone who is unfriendly, rude, and bad-tempered. Both words can be used to describe someone who is foul-tempered.