Weak type of cleaner conserving fancy silk (7)
I believe the answer is:
Here is my best explanation:
'weak type' is the definition.
(I've seen this before)
'cleaner conserving fancy silk' is the subsidiary indication.
'cleaner' becomes 'mop' (something which 'cleans').
'conserving' indicates putting letters inside.
'fancy' is an anagram indicator.
'silk' is an anagram of 'ilks'.
'mop' going around 'ilks' is 'milksop'.
'of' is the link.
(Other definitions for milksop that I've seen before include "Doormat", "Feeble and effete person", "Wimpish fellow", "Feeble youth", "Namby-pamby", "(Young) wimp", "Ineffectual man", "Weak type", "soft fellow" and "Weed".)