you/he/she must be jokingidiom
Definition of you/he/she must be joking
—used say that what someone is saying is very surprising or hard to believe "He said the report is due by tomorrow." "He must be joking."
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
- On Contractions of Multiple Words
- A Look at Uncommon Onomatopoeia
- Is Singular 'They' a Better Choice?