Nonsense about outsize bird group (5)
I believe the answer is:
roost
'bird group' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'nonsense about outsize' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'about' indicates putting letters inside.
'outsize' becomes 'os'.
'rot' placed around 'os' is 'ROOST'.
Can you help me to learn more?
(Other definitions for roost that I've seen before include "unwelcome to come home to?" , "(Bird) settle for night" , "Hen's resting place" , "Where bats congregate" , "Where birds rest at night" .)