Etymology: Middle English hevy, from Old English hefig; akin to Old High German hebīc heavy, Old English hebban to lift — more at heave
Date: before 12th century
1 a: having great weight; also: characterized by mass or weight <how heavy is it?>b: having a high specific gravity : having great weight in proportion to bulk c (1)of an isotope: having or being atoms of greater than normal mass for that element (2)of a compound: containing heavy isotopes 2: hard to bear; specifically:grievous, afflictive<a heavy sorrow> 3: of weighty import :serious<heavy consequences> 4:deep, profound<a heavy silence> 5 a: borne down by something oppressive :burdenedb:pregnant; especially: approaching parturition 6 a: slow or dull from loss of vitality or resiliency :sluggish<a tired heavy step>b: lacking sparkle or vivacity :drabc: lacking mirth or gaiety :dolefuld: characterized by declining prices 7: dulled with weariness :drowsy 8: greater in quantity or quality than the average of its kind or class: as a: of unusually large size or amount <a heavy turnout><heavy traffic>b: of great force <heavy seas>c: threatening to rain or snow d (1): impeding motion (2): full of clay and inclined to hold water e: coming as if from a depth :loud<heavy breathing>f:thick, coarse<heavy syrup>g:oppressive<a heavy odor><heavy weather><rule with a heavy hand>h:steep, acutei:laborious, difficult<heavy going>j:immoderate<a heavy smoker>k: more powerful than usual for its kind <a heavy cavalry><a heavy cruiser>l: of large capacity or output 9 a: very rich and hard to digest <heavy desserts>b: not properly raised or leavened <heavy bread> 10: producing goods (as coal, steel, or chemicals) used in the production of other goods <heavy industry> 11 a: having stress <a heavy rhythm> —used especially of syllables in accentual verse b: being the strongest degree of stress in speech 12: relating to theatrical parts of a grave or somber nature 13:long 9 <heavy on ideas> 14:important, prominent<a heavy politician>
— heavi·nessnoun
synonymsheavy, weighty, ponderous, cumbrous, cumbersome mean having great weight. heavy implies that something has greater density or thickness than the average of its kind or class <a heavy child for his age>. weighty suggests having actual and not just relative weight <a load of weighty boxes>. ponderous implies having great weight because of size and massiveness with resulting great inertia <ponderous elephants in a circus parade>. cumbrous and cumbersome imply heaviness and bulkiness that make for difficulty in grasping, moving, carrying, or manipulating <wrestled with the cumbrous furniture><early cameras were cumbersome and inconvenient>.