anagram vs antigram

anagram and antigram both are nouns.

Word	Noun	Adjective	Verb	Adverb
anagram	Yes	No	Yes	No
antigram	Yes	No	No	No

As nouns, antigram is a hyponym of anagram; that is, antigram is a word with a more specific, narrower meaning than anagram:

anagram: a word or phrase spelled by rearranging the letters of another word or phrase
antigram: an anagram that means the opposite of the original word or phrase

anagram (noun)	antigram (noun)
a word or phrase spelled by rearranging the letters of another word or phrase	an anagram that means the opposite of the original word or phrase

anagram (verb)	antigram (verb)
read letters out of order to discover a hidden meaning