There’s a great line in an episode of Blackadder Goes Forth, when General Melchett instructs his aide-de-camp to make a note of the word “Gobbledegook” because he wants to use it more often in conversation.
I’ve got my own list of words I’d like to use more often in conversation if the situation ever arose, with the current favourite being “Shenanigans”. I so rarely get to use it, though.
What words do you have a mental note to use more often, but so rarely actually get the chance to do so?
I love the word ‘frust’, but it doesn’t come up in polite conversation ever, really. So when I’m being all domestic and sweeping the floor, I address the frust personally. 
Sorry…that’s all I’ve got. All sorts of other big and obscure words I use regularly just to piss-off my work colleagues.
I need to just stick to plain old ordinary words. The last odd word I used out loud was “detritus,” which I didn’t think was all that odd a word, especially in context. (Getting the detritus from last school year out of my son’s room, in preparation for new school stuff.)
My coworker did not know what it meant and asked about it–since we are editors and are interested in words. I said maybe I’d mispronounced it. No. Or used it wrong. No…by this time she had it in her sights, I mean in the dictionary. No, she just hadn’t heard it before.
Too bad, because this one could come up in conversation a lot.
“Abound” - As in “Egad chum, mysteries abound!”
I try to use “supple” at least once a month. Unfortunately it’s usually something like “Hey, the fans in these new switches blow the heat out the front. Sure does keep the fibre supple, tho”
I managed to get the Managing Director of a UK train operator to say the word “Retromingent” during a formal meeting.
Huh. That’s one of those words that I’ve only ever seen in print, so while I *thought *I knew how to pronounce it, I was completely wrong. I just looked it up now, and it’s “dih-TRY-tus”. I wouldn’t have recognized it by hearing it, even though it’s a great word.
(I thought it was “DEH-trih-tus”)
As for the OP, I love the word “seafoam”, but you’d be surprised how often it doesn’t come up.
I like introducing odd words to people. I love the way superfluous rolls off the tongue. I also am currently using the word spiffy. I know, common enough words, but they make other people stare
I don’t keep a list, though, I just find excuses to shove new words in now and then when they come across my radar. Malodorous and mellifluous have been used recently. Yeh, I guess I like -uous and -ous words.
ETA: I love the word detritus – I use it far too often, lol!
“Lethoso,” for which there is no meaning, but I wish there were. So when pedants correct me for mispronouncing the African nation of “Lesotho,” I could counter-correct them back.
Pusillanimous
Poltroon
Plummet
Strewth
Monkeyshines
‘Spiffy’ is the adjective I use for my Triumph and my coconut pork pie hat.
Just the other day I was able to use both defenestrate and copacetic in the space of an hour.
It was wonderful.
Which reminds me: Jettison.
While a crew might jettison the jetsam, does the sea flottison the flotsam?
Righteous.
(I’m a fan of indignation)
Debacle. Imprimatur. Supercilious.
Oh good. For a moment there, I thought you were a fan of '80s surfer slang.
In the late-1970s we used that in the same way people now use ‘Awesome!’
Yes. It comes to shore with the seafoam.
BOOYAH!
Hey, me too! I wasn’t even motivated to look it up, figuring I already knew it and all, so you saved me from an embarrassing mispronunciation as well.
Thanks 
Pescetarian. Now I just need to convert so I can be a pescetarian Episcopalian and I’ll be all set!
Not so much now, but I wish I knew the word “crapulent” back in my drinking days. The years 1988-1992 (inclusive) were frequently crapulent.