Clock
Etymology
Rooted in Black and Latino ballroom culture and in African American Vernacular English, where to “clock” someone means to observe, catch, or see through them. It was later widely used for detecting something a person is trying to conceal — reading past a presented surface — and has spread into general use for simply noticing or perceiving anything quickly.
verb · /KLOK/
To notice, perceive, or size someone or something up instantly.
What it names
It names quick, accurate perception — catching a detail, a mood, or a person’s real intent in a single beat. To clock something is to register it sharply, often before others do, and the word carries a note of shrewd, unsentimental seeing.
Example
She clocked the tension in the room the moment she walked in.
Related idea
Sharper than merely noticing: to clock something is to perceive it decisively and often to grasp what lies behind it.