enough可以是副词,限定词,或代词
限定词 determiner：Have you made enough copies?Is there enough room for me?
副词 adverb：This house isn't big enough for us.She's old enough to decide for herself.
代词 pronoun：Six bottles should be enough.Have you had enough (= to eat)?
你举的两个例子fool enough& big enough 都是副词.英式英语中enough没有所谓的“形容词”此行,determiner的用法类似于形容词词性,因为作为determiner时,enough多放在复数或不可数名词前,表示as many or as much as somebody needs or wants