They lack maybe what’s needed for entrance (8)
I believe the answer is:
latchkey
'needed for entrance' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'they lack maybe' is the wordplay.
'maybe' indicates anagramming the letters.
'they'+'lack'='theylack'
'theylack' with letters rearranged gives 'LATCHKEY'.
'what's' is the link.
Can you help me to learn more?
(Other definitions for latchkey that I've seen before include "Common device to open outer door" , "Means of entry to (parentless?) house" , "Front door opener (for children with absent parents?)" , "A supposed freedom from domestic restrictions" , "Sort of self-reliant child" .)