LGBT vs LGBTQ

LGBT and LGBTQ both are nouns.

Word	Noun	Adjective	Verb	Adverb
LGBT	Yes	No	No	No
LGBTQ	Yes	No	No	No

As nouns, LGBT and LGBTQ are synonyms defined as:

LGBT and LGBTQ: the community of people who have a non-normative gender and/or sexual identity, including lesbian, gay, bisexual, transgender, intersex, or asexual

Other synonyms of LGBT include LGBT+, LGBTQIA+, LGBTQIA.

LGBT (noun)	LGBTQ (noun)
the community of people who have a non-normative gender and/or sexual identity, including lesbian, gay, bisexual, transgender, intersex, or asexual	the community of people who have a non-normative gender and/or sexual identity, including lesbian, gay, bisexual, transgender, intersex, or asexual