Husband and wife changing in tent, perhaps are too hot (7)
I believe the answer is:
swelter
'husband' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for swelter that I've seen before include "Suffer when too hot" , "Be uncomfortably hot as in the sun" , "Sweat and feel faint" , "Be too hot; Gormenghast chef" , "Wrestle (anag)" .)