'Occupy' is Latin for 'seize completely' — from 'capere' (to take), intensified by 'ob-' (over).
To reside or have one's place of business in; to fill or take up a space or time; to take control of a place by military force.
From Old French 'occuper' or directly from Latin 'occupāre' (to seize, to take possession of, to fill, to employ), composed of 'ob-' (against, over) + 'capere' (to take, to seize, to hold), from PIE *keh₂p- (to grasp, to seize). The root *keh₂p- is among the most productive in Indo-European: Latin 'capere' generated 'capture', 'capable', 'capacity', 'accept', 'except', 'conceive', 'deceive', 'perceive', 'receive'; 'capax' (able to hold); and the legal concept of 'capitis' (head, person — as the legal subject who seizes or is seized). Greek 'kaptein' (to gulp down
In the sixteenth and seventeenth centuries, 'occupy' developed a slang meaning of 'to have sexual intercourse with,' which became so widespread that polite speakers avoided the word entirely for over a century. Shakespeare alluded to this in Henry IV Part 2: 'A captain! God's light, these villains will make the word as odious as the word occupy.' The taboo faded by the eighteenth century.