Hot spot in a sea that's rough (10)
I believe the answer is:
passionate
'hot' is the definition.
(similar in meaning)
'spot in a sea that's rough' is the wordplay.
'that's rough' is an anagram indicator (a rough or broken ordering of the letters).
'spot'+'in'+'a'+'sea'='spotinasea'
'spotinasea' is an anagram of 'PASSIONATE'.
(Other definitions for passionate that I've seen before include "enthusiastic" , "Showing intense feeling" , "Showing strong emotions" , "Burning" , "Strongly emotional" .)