Stress shown by Conservative wearing new suit (5)
I believe the answer is:
ictus
'stress' is the definition.
(I've seen this in another clue)
'conservative wearing new suit' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'wearing' indicates putting letters inside.
'new' indicates anagramming the letters.
'suit' is an anagram of 'itus'.
'c' inserted within 'itus' is 'ICTUS'.
'shown by' is the link.
(Other definitions for ictus that I've seen before include "Metrical stress" , "Seizure" , "Is cut (anag.)" , ""fit"" , "recurrence of disease results" .)