adjective
very best, supreme
B1
Means 'very best' or 'supreme'. It's an absolutive superlative adjective often used as emphatic form (not gradable). Not a participle. Use attributively or predicatively as intensifier; there is no comparative form because it's already maximal. Rare and emphatic in everyday German.
Examples
Ihr Service war allerbest und hat uns sehr beeindruckt.
Their service was supreme and really impressed us.
Die Jury bewertete das Projekt als allerbest, obwohl einige Gutachter noch Kritik äußerten.
The jury rated the project as the very best, although some reviewers still voiced criticism.
Das ist das Allerbeste, was ich je gegessen habe.
That's the very best I've ever eaten.
Details
Mnemonics
Imagine a trophy labeled 'Allerbest' placed on the highest podium.
Sounds like 'all our best' — think of the absolute top of everything.
Notes
An emphatic superlative form; somewhat expressive/poetic. Not commonly used in everyday neutral speech.