The word "comedians" is a plural noun -- it appears an apostrophe was omitted. The spellings that are used with other nouns are possessive nouns, not adjectives, although they perform a similar function.
The spelling comedian's is the singular possessive noun (of or about one comedian).
The spelling comedians' is the plural possessive noun (of or about more than one comedian).
In the sentence 'Who were all comedians?' the word 'who' is an interrogative pronoun; the word 'were' is the verb; the word 'all' is an adjective describing the noun 'comedians'.
"Who were all comedians" is a adjective clause (a relative clause), for example:Jack Benny, Milton Berle, Burns and Allen, Stu Erwin, and The Goldbergs, who were all comedians, were TV stars of the early 1950s.The relative clause 'who were all comedians' is a clause introduced by the relative pronoun 'who' and relates back to and further describes the subject nouns (names).See the links below for simple descriptions of adjective and adverb clauses.
adjective
Dark can be an adjective or a noun. Darkly is an adverb.
Night: noun an: adverb adjective: adjective noun: noun adverb: adverb
Adverb.Here is an adverb, not an adjective.
An adverb describes a verb, an adjective or another adverb.
its an adverb an adjective is a descriptive word an adverb is a feeling
It can be an adjective OR an adverb. adjective -- You dog is a friendly dog adverb -- She always talks friendly to me
The adjective of strength is strong.The adverb of strength is strongly.
adverb. it doesn't modify a noun or a pronoun
Nervous is an adjective. The adverb form is nervously.