einzig meaning and definition in german

When followed by another adjective, einzig is typically used in the bare form: die einzig richtige Antwort ("the only correct answer"). However, it is just as correct to follow the general practice and decline both: die einzige richtige Antwort.
Colloquially, an intensified form einzigst- (formally a superlative) is often heard. This is non-standard usage.