Splendid mother with light-hearted mood in charge (8)
I believe the answer is:
majestic
'splendid' is the definition.
(I've seen this before)
'mother with light-hearted mood in charge' is the wordplay.
'mother' becomes 'ma' (Ma is another word for mother or mum).
'with light hearted mood' becomes 'jest' (I can't justify this - if you can you should believe this answer much more).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'ma'+'jest'+'ic'='MAJESTIC'
Can you help me to learn more?
(Other definitions for majestic that I've seen before include "Regal - grand" , "Impressively beautiful" , "Stately; sublime" , "Stately, dignified or grand" , "Splendid, regal" .)