Summer footwear (4-5)
(Other definitions for flip-flops that I've seen before include "Casual footwear - backward hand springs" , "Beach shoes with toe thong" , "Casual sandals" , "Informal footwear" , "Beach footwear" .)
'summer footwear' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sandals that I've seen before include "Open footwear" , "Light open shoes" , "Soles strapped to the feet" .)