Misgendering refers to using gendered/nongendered pronouns (he, she, they, xe, e, etc.) to refer to someone who would prefer you to use other pronouns, e.g., referring to a woman using the masculine pronoun "he". Misgendering transgender people might be done accidentally, or may be done deliberately to assert a rejection of their gender identity.
When done deliberately, transgender people ordinarily consider this deeply disrespectful and insulting. I'm wondering if this would be classified as backbiting which is forbidden in Qur'an 49:12 "...And do not spy or backbite each other..." (and Qur'an 104), or if it would be classified as something else, like slandering, or something I haven't thought of.
Question: Is deliberately misgendering a transgender person a form of backbiting?
There's this hadith:
... Thereupon he (the Holy Prophet) said: Backbiting implies your talking about your brother in a manner which he does not like. It was said to him: What is your opinion about this that if I actually find (that failing) in my brother which I made a mention of? He said: If (that failing) is actually found (in him) what you assert, you in fact backbited him, and if that is not in him it is a slander. -- Sahih Muslim 2589 (sunnah.com)
But I'm not sure how to apply it. The part "...in a manner which he does not like" certainly applies, but the second part "If (that failing) is actually found..." doesn't seem to apply here.
Here's a circumstance where an appropriate answer to this question would be required:
Someone deliberately misgenders someone I know. I have transgender friends, and not everyone's familiar with transgender-related matters, so this is plausible.
I explain to them that it's backbiting, which is forbidden, with the intention of forbidding what is evil (Qur'an 3:104).
However, since it's impermissible to talk without knowledge (Qur'an 17:36), nor may I declare something haram which is halal (Qur'an 10:59), I better be 100% certain that it is actually backbiting before saying it's backbiting.