na-adjective, noun which may take the genitive case particle 'no', noun
nonexistent; nothing at all; completely lacking
Emphatic word meaning that something is entirely absent. Often used in formal or written contexts. The gloss 'bugger-all' is vulgar slang and should be used with caution.
There is absolutely no evidence for his story.
Crime is virtually nonexistent in this area.
He has absolutely no motivation.
The chance of that plan succeeding is next to nil.
皆目 is an adverb used with a negative verb (皆目わからない, 'not at all understand'), whereas 皆無 is a noun/na-adjective that stands alone to mean 'nonexistent'.
Compound of 皆 (all, everyone) and 無 (nothing, nonexistent). The combination literally means 'all nothing', emphasizing total absence.