cuss

The root cuss comes from Latin quatere, "to shake or strike," with the past participle quassus. When quatere joined a prefix, two things changed: the present stem became -cutere and the participle became -cussus. Almost every English word in this family descends from that -cussus participle, which is why they nearly all end in -cuss or -cussion.

Start with the most literal one. per- (through) + quatere → percussion: striking something thoroughly to make it sound. Hit a drum, a tambourine, a xylophone, and you are doing percussion. A musician who specializes in it is a percussionist. The image is direct: a hand or stick striking, again and again.

Now shake harder, and aim at the head. con- (intensive, "thoroughly") + quatere → concussion: a violent shaking. Originally it meant any forceful collision, but medicine narrowed it: when the brain is shaken hard inside the skull from a blow, that is a concussion. The Latin idea of shaking survives almost untouched — your brain literally got rattled.

Then add a bounce. re- (back) + per- (through) + quatere → repercussion: a striking that comes back through. The first meaning was physical — an echo, a recoil, a sound bouncing back. From there it drifted to the abstract: the return blow of an action, the consequences that come rebounding at you later. Today repercussions (usually plural) are the unwelcome aftershocks of a decision — you do something, and it strikes back.

The most surprising member is discuss. dis- (apart) + quatere → "to shake apart." Romans used discutere for scattering or shattering something by striking it. But the metaphor turned intellectual: to shake an idea apart, to break a topic into pieces and look at each one. That is exactly what we do when we discuss something — we don't strike it physically, we take it apart in conversation. The noun is discussion.

A few cousins live just outside this list. quash (to put down, annul) comes from the same quassāre — to crush by shaking. rescue traces back through Old French to ex- + quatere, "to shake out / free." succussion (a shaking, used in medicine) and concuss (the verb behind concussion) are rarer family members. The pattern to remember: the prefix tells you the direction of the blow — through (per), back (re-per), apart (dis), thoroughly (con) — and cuss is always the strike itself.