You should hyphenate the words "mother in law."
To connect two words or parts of a word with a hyphen.
She is a hyphenate with the last name Smith-Jones.
A person who has a hyphenated name, typically combining two family names.
His hyphenate surname is very unique.
Describing a name that includes a hyphen between two parts.
शक्तिशाली मुफ्त चित्र शब्दकोश और फ्लैशकार्ड्स के साथ।
