The phrase "lower framerate" means that the speed at which images or videos are displayed on a screen is reduced, so things may appear to move more slowly or less smoothly. Full definition
The way the game looks now is fine by me, and I actually wish more games would be at lower framerates because the higher framerate looks cheesy. (gonintendo.com)
These include two fixes addressing a problem that caused low framerates on Windows Mixed Reality headsets. (digitaltrends.com)
It's playable, but low framerates from time to time with dips to around 20 fps, but mostly holds 30 ish. (thevitalounge.net)