very sudden; extremely abrupt
A yojijukugo emphasizing an action or event that is shockingly sudden and without warning. Often used in formal or literary contexts.
The room fell silent at his extremely abrupt remark.
唐突千万な話で恐縮ですが、本題に入らせていただきます。
I apologize for the suddenness, but let me get straight to the point.
唐突 means 'sudden' or 'abrupt' and is more common in everyday speech. 唐突千万 is a stronger, more emphatic yojijukugo form.
突然 is the standard word for 'suddenly' and is neutral in register. 唐突千万 is more literary and carries a nuance of being shockingly abrupt.
A yojijukugo combining 唐突 (sudden, abrupt) with 千万 (extremely, myriad) to intensify the meaning. The exact historical derivation is uncertain, but it follows a common pattern of intensifying a two-character word with 千万.