Stay in control hosting mother (6)
I believe the answer is:
remain
'stay' is the definition.
(synonyms)
'control hosting mother' is the wordplay.
'control' becomes 'rein' (synonyms).
'hosting' is an insertion indicator (inserted letters are welcomed in or hosted).
'mother' becomes 'ma' (ma can mean mother).
'rein' going around 'ma' is 'REMAIN'.
'in' is the link.
(Other definitions for remain that I've seen before include "Stay or continue to be" , "Stay around" , "Marine (anag)" , "Don't leave (the EU?)" , "Survive" .)