Having a day out, being very noisy is silly (5)
I believe the answer is:
daffy
'is silly' is the definition.
(I've seen this before)
'having a day out being very noisy' is the wordplay.
I cannot really see how this works, but
'a' is present in the answer.
'day' could be 'd' (abbreviation for day) and 'd' is found in the answer.
'noisy' could be 'ff' and 'ff' is present in the answer.
A single letter 'y' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for daffy that I've seen before include "Silly, mildly eccentric" , "Cuckoo" , "duck on screen" , "Film duck" , "Crazy" .)