The word in question was antsy (not to be confused with Ansty, a village in Sussex whose (shared) sign on the A23 I consistently misread as Antsy Cowfold, thus self-inducing the giggles). I only discovered that antsy was American when the Association of British Scrabble Players moved to a combined British-American dictionary (soon to be replaced by another one). Antsy is an important word to Scrabblers because of its comparative form: antsier. Competitive Scrabble players tend to study "stems", typically 6-letter combinations that have a high probability of making a 7-letter word when combined with one more letter, and thus using all of the tiles on one's rack. Doing so results in a 50-point bonus score, and thus is called a bonus word in BrE and a bingo in AmE Scrabble circles. Antsier is a case of RETAIN+S, and RETAIN is one of the first stems a Scrabble geek learns. (I say geek [orig. AmE] in the proudest possible way.)
But what does antsy/antsier mean? To a Scrabble fiend it should not matter, but I'll tell you anyway. The first meaning is 'fidgety, restless', that is, acting like one has ants in one's pants (orig. AmE), and it's often assumed to have derived from that idiom, although there is some evidence to the contrary. Thus, the goal in my lectures is to keep the students from getting antsy. If I see them starting to shift around in their chairs, I tell them something outrageously untrue to keep them interested. Oh wait, sorry, that's what I do when I can sense your attention starting to wander away from this blog. Maybe I should have done it back in the Scrabble paragraph.
By extension, antsy can also mean 'nervous, apprehensive'. So, I might start getting antsy before my first lecture of term. Or maybe my students will. I was very relieved when, about two years ago, I finally stopped having teaching anxiety dreams before every single term. I should probably (AmE) knock on/(BrE) touch wood now that I've said that. Maybe they stopped because parts of the dreams started coming true--such as students take phone calls during class.
By the way: HBBH! (LynneE for: Happy Birthday, Better Half! A few minutes belatedly!)