Weak type of cleaner conserving fancy silk (7)
I believe the answer is:
milksop
'weak type' is the definition.
(I've seen this before)
'cleaner conserving fancy silk' is the wordplay.
'cleaner' becomes 'mop' (something which 'cleans').
'conserving' means one lot of letters goes inside another.
'fancy' is an anagram indicator.
'silk' anagrammed gives 'ilks'.
'mop' enclosing 'ilks' is 'MILKSOP'.
'of' is the link.
(Other definitions for milksop that I've seen before include "Inefectual man" , "Cissy (informal) -- limps OK (anag)" , "(Young) wimp" , "Wimpish fellow" , "Weak type" .)