I hate the phrase, “if you catch my drift.” I think it sounds stupid and it doesn’t even make much sense. What is my drift and why should anyone have to catch it?
Oddly enough, your favorite phrase has become idiomatic over the course of centuries. Way back in the fifteen-double-aughts, “drift” was a common enough word for the general thrust of conversation; the literal meaning being “what I am driving at,” since “drift” and “drive” share a common route. The letters F, V, and their lesser cousin, B, kind of blend together in etymology like that. “The drift” could even be the intent itself, as in, “My sole drift is to answer your questions.” The seafaring idea of a ship drifting in the ocean currents actually comes about later, although not much, and is derived from a sense of being driven by the motion of the ocean.
While you’re right that “if you catch my drift” smacks of obscurity inasmuch as we’d never use the word outside of the popular idiom, there’s something to appreciate about the subtle implications of the phrase. I like that there’s a strong sense of oblique motion, as though the course of conversation isn’t exactly clear, yet sooner or later the inevitable meaning will accumulate like detritus on the seashore or snow piling in drifts at the edge of a parking lot. While the direction may not be immediately obvious, it’s also not aimless. “To catch my drift” is to pick up on the subtle undercurrents that drive my point home across however many miles of oceanic vagueness. There’s also no denying that it’s more elegant than “hint hint nudge nudge wink wink say no more.”