Crossword Genius

Free one with sex brought up (6)

Ross

I believe the answer is:

untied

I'm a little stuck... Click here to teach me more about this clue!

'free' is the definition.
(synonyms)

'one with sex brought up' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'un' (northern English dialect form of 'one') and 'un' is present in the answer.
The remaining letters 'tied' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

(Other definitions for untied that I've seen before include "'Unfastened, lace say (6)'" , "Released from 19" , "Undid the knot" , "Unfastened, unlaced" , "Lacking any fetters" .)

I've seen this clue in The Telegraph.
Want a hint initially instead of a full solution? Install my app