Under emotional strain in past, perhaps (5)
I believe the answer is:
tense
I believe this is a double definition.
'under emotional strain' is the first definition.
(I've seen this before)
'past perhaps' is the second definition.
(grammar)
'in' acts as a link.
(Other definitions for tense that I've seen before include "Taut, strained" , "Rigid; verb form" , "Verb form, indicates time" , "Verb form; uptight" , "Drawn" .)