Knitter knitted a little ornament (7)
I believe the answer is:
trinket
'a little ornament' is the definition.
'trinket' can be an answer for 'ornament' (I have seen 'Small ornament' mean 'trinket' so perhaps 'ornament' could also mean 'trinket'). I'm unsure of the 'a little' bit.
'knitter knitted' is the wordplay.
'knitted' indicates an anagram (knit can mean to screw up or crease).
'knitter' is an anagram of 'TRINKET'.
Can you help me to learn more?
(Other definitions for trinket that I've seen before include "Small item of jewellery" , "Cheap ornament" , "Charm" , "Knick-knack" , "Trifle" .)