'Oppress' is Latin for 'press against and crush' — tyranny imagined as crushing weight from above.
To keep someone in subjection and hardship by the unjust exercise of authority or power; to weigh heavily on the mind or spirits.
From Old French 'opresser,' from Medieval Latin 'oppressare,' a frequentative of Latin 'opprimere' (to press against, press down, crush), composed of 'ob-' (against) and 'premere' (to press). The Latin verb had both physical senses (to crush, smother, overwhelm by weight) and political ones (to put down, subjugate). English inherited both: the physical sense of bearing down with crushing weight and the political sense of exercising tyrannical power
In classical Latin, 'opprimere' could mean 'to fall upon someone unexpectedly' — essentially, to ambush. The element of surprise combined with the element of weight. Roman historians used it for sudden military attacks where the enemy was literally pressed down and crushed before they could react. The political sense of sustained tyranny developed later, losing the surprise element but keeping