this isn't merriam-webster, but i reckon it's when you're motivated by something other than what you should be.

say you come out of the cinema with your friends and you start raving about how many of the shots were inspired by some french new wave guy.

maybe you're authentically stoked about the cinematography (the pretense), but maybe you mostly just want to sound smart about movies because of how it affects your status in the group.

someone who loves film for its own sake should be happy to talk about the film at any level with their friends. people aren't familiar with godard? that's okay, you could also talk about the acting or the story. if you're incapable of meeting people where they're at, i think people will be rightfully suspicious that you've got an ulterior motive.

sometimes accusations of pretentiousness are just anti-intellectual. i've been called pretentious for referencing the history of a genre of music as part of my appreciation for a song. it felt genuine to me at the time, and i wish the person who said that had just said "i don't know enough about that to engage in the same way and i don't want to hear a lecture." or "yeah... i liked a different aspect of it." instead it was basically like "shut up, nerd."

it takes two. one to notice that their passion is alienating their interlocutor and one to engage supportively if someone seems excited to talk about a subject they love.

this stuff all gets worse if you're talking about disliking something. if someone's perfomatively liking something, it's easier to overlook that it's pretend. if they're being a hater, it's a bad deal: being persuaded to enjoy something less in order to feel insecure about my inferior taste.¹

pretentiousness doesn't have to be about taste or aesthetics. i was pretentious the other day when i got in a little back-and-forth with my driving theory instructor about whether or not he had explained something correctly. ostensibly i was speaking up to clarify for myself and my fellow students, but once he began to double-down on his confusing explanation and i started to try to explain to him why it was confusing, i could feel my motivation shift to something else: i wanted to outdo him and show that i was smart to the group.²

it's hard to know what the exact mix of any of our motivations is. i like to flex my vocabulary in a way that is a little pretentious, but i also genuinely enjoy finding the word that feels like it perfectly conveys what i'm trying to say. having multiple motivations isn't necessarily pretentious, but you should try to reduce the amount you decieve yourself or others as to what they are.