the word 'straightjacket' is a variant of the earlier term 'straitjacket', which more transparently reveals its etymology. 'strait' derives from latin strictus, meaning 'drawn tight, narrow, or confined'. over time, due to pronunciation and spelling association with the more common word 'straight', the form 'straightjacket' became standard. the literal meaning, a tight-fitting jacket used to confine the arms, evolved from the combination of 'strait' (confining) and 'jacket' (a garment). the modern figurative sense, denoting anything that severely restricts freedom, logically extends from the physical restraint imposed by the device.

Structure: straight + jacket straight (from middle english streght, meaning 'not bent or curved', of germanic origin); jacket (from old french jaquet, a diminutive of jaque, meaning 'a short, close-fitting coat', of uncertain origin).