One obviously too hot wearing this? (7)
I believe the answer is:
sweater
'one obviously too hot wearing this?' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for sweater that I've seen before include "Clobber" , "mugger once" , "Jumper (7)" , "person in a sauna?" , "Guernsey" .)