Is "motionless" an adverb or adjective? [duplicate]

He left home young

He died young

Does the word "young" act as either a predicative complement or a incidental adverbial in those sentences？And how to distinguish them?

It is not always simple to distinguish adverbial from adjectival usage in this sort of construction. Is the word in question saying something more about the (often subject) noun, or about the action/process?

In 'he hammered the metal flat', 'flat' is a predicative adjective showing the final state of the metal. This is a resultative construction.

In 'he hammered the metal frenziedly', 'frenziedly' is an adverb adding description to the verb[al action].

In 'he shot wide', it is arguable whether 'wide' is describing the final situation (of the ball's position) or the woeful manner of shooting. 'Wide' can be a flat adverb (eg 'travelled far and wide').

However, in 'he died young', 'young' is obviously not telling us anything (directly) about the manner of his death, but something about his condition when he died: ie 'young' modifies the (subject) pronoun, and this is therefore a subject-orientated depictive construction, with 'young' an adjective.