i Register
In some senses, mum is marked as informal, archaic, obsolete, slang, dated. Watch for register when choosing this word.
ADJ
young | single, unmarried | career, working | proud | expectant, pregnant (also mum-to-be)
new
My sister became a new mum last month and is still getting used to sleepless nights.
surrogate
The elderly neighbour became a loving surrogate mum to the children after their parents moved abroad.
PHRASES
mum and dad