1.  lowering(n = noun.act) - the act of causing to become less;
is a kind of decrease, diminution, reduction, step-down
has particulars: tapering
Derived forms verb lower₃, verb lower₄

2.  lowering(n = noun.act) letting down - the act of causing something to move to a lower level;
is a kind of movement
Derived form verb lower₁

   lowering(s = adj.all) heavy, sullen, threatening - darkened by clouds; "a heavy sky"

   Dark and threatening; gloomy; sullen; as, lowering clouds or sky. [1913 Webster]

N  dejection, dejectedness, depression, prosternation, lowness of spirits, depression of spirits, weight on the spirits, oppression on the spirits, damp on the spirits, low spirits, bad spirits, drooping spirits, depressed spirits, heart sinking, heaviness of heart, failure of heart, heaviness, infestivity, gloom, weariness, taedium vitae, disgust of life, mal du pays, anhedonia, melancholy, sadness, il penseroso, melancholia, dismals, blues, lachrymals, mumps, dumps, blue devils, doldrums, vapors, megrims, spleen, horrors, hypochondriasis, pessimism, la maladie sans maladie, despondency, slough of Despond, disconsolateness, hope deferred, blank despondency, voiceless woe, prostration of soul, broken heart, despair, cave of despair, cave of Trophonius demureness, gravity, solemnity, long face, grave face, hypochondriac, seek sorrow, self-tormentor, heautontimorumenos, malade imaginaire, medecin tant pis, croaker, pessimist, mope, mopus, affliction, sorry sight, memento mori, damper, wet blanket, Job's comforter, cheerless, joyless, spiritless, uncheerful, uncheery, unlively, unhappy, melancholy, dismal, somber, dark, gloomy, triste, clouded, murky, lowering, frowning, lugubrious, funereal, mournful, lamentable, dreadful, dreary, flat, dull, dull as a beetle, dull as ditchwater, depressing, melancholy as a gib cat, oppressed with melancholy, a prey to melancholy, downcast, downhearted, down in the mouth, down in one's luck, heavy-hearted, in the dumps, down in the dumps, in the suds, in the sulks, in the doldrums, in doleful dumps, in bad humor, sullen, mumpish, dumpish, mopish, moping, moody, glum, sulky, out of sorts, out of humor, out of heart, out of spirits, ill at ease, low spirited, in low spirits, a cup too low, weary, discouraged, disheartened, desponding, chapfallen, chopfallen, jaw fallen, crest fallen, sad, pensive, penseroso, tristful, dolesome, doleful, woebegone, lacrymose, lachrymose, in tears, melancholic, hypped, hypochondriacal, bilious, jaundiced, atrabilious, saturnine, splenetic, lackadaisical, serious, sedate, staid, stayed, grave as a judge, grave as an undertaker, grave as a mustard pot, sober, sober as a judge, solemn, demure, grim, grim-faced, grim-visaged, rueful, wan, long-faced, disconsolate, unconsolable, inconsolable, forlorn, comfortless, desolate, desole, sick at heart, soul sick, heart sick, au desespoir, in despair, lost, overcome, broken down, borne down, bowed down, heartstricken, cut up, dashed, sunk, unnerved, unmanned, down fallen, downtrodden, broken-hearted, careworn, with a long face, with tears in one's eyes, sadly, the countenance falling, the heart failing, the heart sinking within one, a plague of sighing and grief, thick-ey'd musing and curs'd melancholy, the sickening pang of hope deferred.

N  depression, lowering, depression, dip, abasement, detrusion, reduction, overthrow, overset, overturn, upset, prostration, subversion, precipitation, bow, courtesy, curtsy, genuflexion, genuflection, kowtow, obeisance, salaam, depressed, at a low ebb, prostrate, detrusive, facinus quos inquinat aequat.