Less happy about cat, say, climbing large item in tool shed? (10)
I believe the answer is:
stepladder
'item in tool shed?' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'less happy about cat say climbing large' is the wordplay.
'less happy' becomes 'sadder' ('sad' can be the opposite of 'happy' so perhaps 'sadder' is reasonable for 'less happy').
'about' means one lot of letters goes inside another.
'cat say' becomes 'pet' (cats are kept as pets).
'climbing' is a reversal indicator (in a down clue, letters climb up).
'large' becomes 'L' (eg in clothes sizes).
'pet' reversed gives 'tep'.
'tep'+'l'='tepl'
'sadder' enclosing 'tepl' is 'STEPLADDER'.
Can you help me to learn more?
(Other definitions for stepladder that I've seen before include "Short folding climbing frame" , "Portable means of ascent" , "Painter's mate" , "Portable climbing aid" , "Domestic climbing aid" .)