The man with cold, twitching and feverish (6)
I believe the answer is:
hectic
'feverish' is the definition.
('hectic' can be a synonym of 'feverish')
'the man with cold twitching' is the wordplay.
'the man' becomes 'he'.
'with' means one lot of letters go next to another.
'cold' becomes 'c' (eg on taps).
'twitching' becomes 'tic' (tic is a kind of twitching).
'he'+'c'+'tic'='HECTIC'
'and' acts as a link.
(Other definitions for hectic that I've seen before include "Involving feverish activity, flushed" , "Full of frantic activity" , "particularly busy" , "in a rush" , "Bustling" .)