Hot shower steamy, ultimately (7)
I believe the answer is:
peppery
'hot' is the definition.
(synonyms)
'shower steamy ultimately' is the wordplay.
I cannot really understand how this works, but
'shower' could be 'pepper' (I've seen this before) and 'pepper' is present in the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for peppery that I've seen before include "Highly spiced" , "Irritable" , "Very spicy" , "Quick-tempered" .)