Men providing information by the sides of the Thames (5)
I believe the answer is:
gents
'men' is the definition.
(gent is a kind of man)
'information by the sides of the thames' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'by' means one lot of letters go next to another.
'the sides of' says to hollow out the word (remove centre letters) (only the letters on the sides remain).
'thames' with its centre removed is 'ts'.
'gen'+'ts'='GENTS'
'providing' acts as a link.
(Other definitions for gents that I've seen before include "Male loos" , "Men (colloq.)" , "toilet" , "Public convenience" .)