Some men become English in the bathroom (2,5)
I believe the answer is:
en suite
'the bathroom' is the definition.
(I've seen this before)
'some men become english' is the wordplay.
'some men' becomes 'en' (I can't justify this - if you can you should give a lot more credence to this answer).
'become' becomes 'suit' (synonyms).
'english' becomes 'E' (abbreviation).
'en'+'suit'+'e'='EN SUITE'
'in' is the link.
Can you help me to learn more?
(Other definitions for en suite that I've seen before include "Attached as part of a unit, bathroom say" , "Like bathrooms next to bedrooms" , "(Of a bedroom) having a private bathroom attached" , "(Of bathroom) accessible from the bedroom" , "Forming a single unit, like bedroom and bathroom" .)