Baby's gear would be smart on Sunday (5)
I believe the answer is:
nappy
This clue could be a double definition.
'baby's gear' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'smart on sunday' is the second definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?
'would be' acts as a link.
Can you help me to learn more?
(Other definitions for nappy that I've seen before include "Item for baby" , "Baby garment" , "Baby's garment" , "Baseball fielder" , "One pinned on baby" .)