What does the cryptic crossword clue "A little heat coming through leather muffler (5)" mean?

The definition is "A little heat". The wordplay uses a hidden word. Hidden in "a little heat coming through leaTHER Muffler" The answer is THERM.

A little heat coming through leather muffler (5)

Times Cryptic #28641 | 4 Down | 2023-06-28 flower