"weighted or pressed down," physically or mentally, late 14c., past-participle adjective from oppress.
Ovirredyn with a carte-wheel, The chyld oppressyd lay in the streete deed. [John Lydgate "Lives of Ss. Edmund & Fremund and the Extra Miracles of St. Edmund," mid-15c.]
oppressed by a sense of failure
oppose
opposite
opposition
oppositional
oppress
oppressed
oppression
oppressive
oppressor
opprobrious
opprobrium