1580s, "to torture" (trans.), from French agoniser (14c.) or directly from Medieval Latin agonizare "to labor, strive, contend," also "be at the point of death," from Greek agonizesthai "contend in the struggle, contend for victory or a prize" (in reference to physical combat, stage competitions, lawsuits), from agonia "a struggle for victory," originally "a struggle for victory in the games" (see agony). Intransitive sense of "suffer extreme physical pain" is recorded from 1660s; mental sense of "to worry intensely" is from 1853. Related: Agonized; agonizing.