Hindus take off clothing and start to swim here? (5)
I believe the answer is:
indus
'here?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'hindus take off clothing and start to swim' is the wordplay.
'take off clothing' means to look at the middle letters (letters which clothe the rest are removed).
'and' means one lot of letters go next to another.
'start to' suggests taking the first letters.
The central letters of 'hindus' are 'indu'.
The initial letter of 'swim' is 's'.
'indu'+'s'='INDUS'
(Other definitions for indus that I've seen before include "Great river of South Asia" , "River flowing from Tibet to the Arabian Sea" , "River of Southern Asia" , "Long Asian river" , "Long river of Asia" .)