The snag with a hot-headed desire (5)
I believe the answer is:
hitch
'the snag' is the definition.
(synonyms)
'with a hot-headed desire' is the wordplay.
'with' means one lot of letters go next to another.
'a hot' becomes 'h' (abbreviation eg on taps).
'headed desire' becomes 'itch' (itch is a kind of desire. I am not sure about the 'headed' bit.).
'h' next to 'itch' is 'HITCH'.
Can you help me to learn more?
(Other definitions for hitch that I've seen before include "Yank" , "Marry" , "unite" , "Tether (rope); difficulty" , "get a free ride" .)