Lodger, perhaps unattached, meets mother with child (9)
I believe the answer is:
freemason
'lodger' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'unattached meets mother with child' is the wordplay.
'unattached' becomes 'free' (I've seen this before).
'meets' is a charade indicator (letters next to each other).
'mother' becomes 'ma' (Ma is another word for mother or mum).
'with' is a charade indicator (letters next to each other).
'child' becomes 'son' (male child).
'free'+'ma'+'son'='FREEMASON'
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for freemason that I've seen before include "who could be in order" , "Forenames (anag)" , "Forenames of one of fraternity with secret rituals" , "Brother" , "secret society member" .)