Monica, to Ross, informally (3)
I believe the answer is:
sis
(Other definitions for sis that I've seen before include "Sibling (informal)" , "spies ..." , "Secret Intelligence Service (abbreviation)" , "Little sibling" , "relative" .)
I believe the answer is:
sis
(Other definitions for sis that I've seen before include "Sibling (informal)" , "spies ..." , "Secret Intelligence Service (abbreviation)" , "Little sibling" , "relative" .)