Sun attempts to keep quiet about beach's standard (5,3,7)
I believe the answer is:
stars and stripes
'standard' is the definition.
(the US flag - standard can mean a flag)
'sun attempts to keep quiet about beach's' is the wordplay.
I cannot quite see how this works, but
'sun' could be 'star' (the sun is a star) and 'star' is found in the answer.
'quiet' could be 'p' (music symbol for 'piano', ie soft or quiet) and 'p' is found in the answer.
'attempts' could be 'tries' ('try' can be a synonym of 'attempt') and 'tries' is found in the remaining letters.
'about' could be 'a' (abbreviation in Chambers) and 'a' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stars and stripes that I've seen before include "indicators of military rank" , "indications of rank" , "Standard" , "American flier" , "The US flag" .)