Sport endlessly followed by one in beachwear (6)
I believe the answer is:
bikini
'beachwear' is the definition.
(I have seen 'Skimpy beachwear ' mean 'bikini' so perhaps 'beachwear' could also mean 'bikini')
'sport endlessly followed by one' is the wordplay.
'sport' becomes 'biking' (biking is a sport).
'endlessly' means to remove the last letter.
'followed' means one lot of letters go next to another.
'by one' becomes 'i' (Roman numeral. I am not sure about the 'by' bit.).
'biking' with its final letter taken off is 'bikin'.
'bikin'+'i'='BIKINI'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for bikini that I've seen before include "Two piece swimsuit" , "Infamous atoll" , "strip of beach" , "Site of A-Bomb tests; resultantly shocking swimwear!" , "providing little cover for swimmers" .)