early 14c., "burden, vex, inconvenience," from Old French encombrer "to block up, hinder, thwart," from Late Latin incombrare, from in- "in" (from PIE root *en "in") + combrus "barricade, obstacle," probably from Latin cumulus "heap" (see cumulus). Meaning "hinder, hamper" is attested in English from late 14c. Related: Encumbered; encumbering.
early 15c., preventen, "act in anticipation of, act sooner or more quickly than (another)," from Latin praeventus, past participle of praevenire "come before, anticipate, hinder," in Late Latin also "to prevent," from prae "before" (see pre-) + venire "to come" (from a suffixed form of PIE root *gwa- "to go, come").
Originally in the literal classical meaning. The meaning "keep from existing or occurring" is by 1540s; the sense of "anticipate to hinder, hinder from action by opposition of obstacles" was in Latin but is not recorded in English until 1660s.
1620s, "to render dwarfish, hinder from growth to the natural size," from dwarf (n.); sense of "to cause to look or seem small by comparison" is by 1829. Related: Dwarfed; dwarfing.
Middle English merren "to deface, disfigure; impair in form or substance" (early 13c.), from Old English merran (Anglian), mierran (West Saxon) "to waste, spoil," from Proto-Germanic *marzjan (source also of Old Frisian meria, Old High German marren "to hinder, obstruct," Gothic marzjan "to hinder, offend"), from PIE root *mers- "to trouble, confuse" (source also of Sanskrit mrsyate "forgets, neglects," Lithuanian miršti "to forget"). For vowel change, see marsh. Related: Marred; marring.
1610s, "to block or stop up with obstacles or impediments," a back-formation from obstruction or else from Latin obstructus, past participle of obstruere "build up, block, block up, build against, stop, bar, hinder," from ob "in front of, in the way of" (see ob-) + struere "to pile, build" (from PIE *streu-, extended form of root *stere- "to spread"). Figurative sense of "to hinder, impede, retard, delay" (justice, the law, etc.) is by 1640s. Related: Obstructed; obstructing.
1530s, originally "to bind up (a corpse);" sense of "hinder, restrain" is from 1727, from trammel (n.), a figurative use from the literal sense "bind (a horse's legs) with a trammel" (c. 1600). Related: Trammeled; trammeling.