the.com/pressure point

means A specific spot — on a body, in a system, or in an argument — where applying targeted force produces an outsized effect.

from Literal first: a point on the body where pressing a nerve or vessel does something disproportionate — stops bleeding, numbs pain, drops someone in a fight (martial arts and first aid both claim it). The figurative sense — the vulnerable spot in a negotiation, a market, a person's resolve — rode in on that physical image sometime in the 20th century, once people needed a way to talk about leverage that didn't require actually touching anyone.