Forces woman to shelter Romeo (4)
I believe the answer is:
army
'forces' is the definition.
(thesaurus)
'woman to shelter romeo' is the wordplay.
'woman' becomes 'amy' ().
'to shelter' indicates putting letters inside.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'amy' going around 'r' is 'ARMY'.
(Other definitions for army that I've seen before include "Organisation for soldiering" , "Ground forces" , "Large military force" , "Multitude" , "Fighting unit" .)