The word 'guardian' is a noun form, a word for a person who looks after and is legally responsible for someone who is unable to manage their own affairs; a defender, protector, or keeper.
The other noun form for guardian is guardianship.Synonyms for the noun guardian are:parentkeeperprotectorcustodianoverseerchaperon (chaperone)shepherdsittertrusteesupervisorwardenwatchdog
No, it is not an adverb. Guardian is a noun, which may be used as a noun adjunct with other nouns, as in guardian angel.
The noun form of the word "guard" is "guardian."
Guardian
The noun form for the adjective horrible is horribleness.
One example is your question. "A parent or guardian must sign this form."
The noun form of the adjective 'prosperous' is prosperousness.A related noun form is prosperity.
The noun form for the adjective glaring is glaringness. Another noun form is glare.
Implication is the noun form of "imply."
ability is the noun form of the adjective able;conversation is the noun form of the verb to converse;dependence is the noun form of the verb to depend;departure is the noun form of the verb to depart;dwelling is the noun form of the verb to dwell;favorite is the noun form of the verb to favor;happiness is the noun form of the adjective happy;information is the noun form of the verb to inform;rarity is the noun form of the adjective rare;weakness is the noun form of the adjective weak;writer is the noun form of the verb to write;writing is also a noun form of the verb to write.
The noun form for the adjective defensive is defensiveness.Another noun form is defense.
The noun form of the adjective obedient is obedience.