1. a day late and a dollar short - Adjective
2. a day late and a dollar short - Adverb
a day late and a dollar short
(US, idiomatic, predicative) Too late and too feeble to achieve the desired effect.
His apology was a day late and a dollar short.
a day late and a dollar short
(US, idiomatic) Adverbial use of the adjectival form.
Help arrived a day late and a dollar short.