Could perhaps show strength (5)
I believe the answer is:
might
This might be a double definition.
'could' is the first definition.
(synonyms)
'show strength' is the second definition.
'might' can be an answer for 'strength' (might is a kind of strength). I am not sure about the 'show' bit.
'perhaps' acts as a link.
Can you help me to learn more?
(Other definitions for might that I've seen before include "Physical strength of old" , "Doubtful" , "Great power/strength" , "May, in the past" , "word expressing possibility" .)