Worthless, mushy stuff, finally obtained free (4-3-7)
I believe the answer is:
good-for-nothing
'worthless' is the definition.
(similar in meaning)
'mushy stuff finally obtained free' is the wordplay.
I cannot quite understand how this works, but
'stuff' could be 'goo' (I have seen 'Sticky stuff ' mean 'goo' so perhaps 'stuff' could also mean 'goo') and 'goo' is present in the answer.
'free' could be 'fornothing' (I've seen this in another clue) and 'fornothing' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for good-for-nothing that I've seen before include "Ultimate sale bargain" , "Worthless person" , "Waster" .)