expression, noun
as different as night and day; chalk and cheese; the moon and a turtle
Idiomatic expression emphasizing that two things are superficially similar but fundamentally different. Often used in the pattern ～と～は月とスッポンだ.
彼の絵と私の絵は月とスッポンだ。
His painting and mine are as different as night and day.
あの二人の
Their personalities are as different as chalk and cheese.