ROGET THESAURUS
flatness
Dullness
N
dullness, heaviness,
flatness, infestivity &c, stupidity want of originality, dearth of ideas, prose, matter of fact, heavy book, conte a dormir debout, platitude, dull, dull as ditch water, unentertaining, uninteresting, flat, dry as dust, unfunny, unlively, logy, unimaginative, insulse, dry as dust, prosy, prosing, prosaic, matter of fact, commonplace, pedestrian, pointless, weary stale flat and unprofitable, stupid, slow, flat, insipid, vapid, humdrum, monotonous, melancholic, stolid plodding, boring, tiresome, tedious, davus sum non Aedipus, deadly dull and boring, DDB.
Horizontality
N
horizontality,
flatness, level, plane, stratum, dead level, dead flat, level plane, recumbency, lying down, reclination, decumbence, decumbency, discumbency, proneness, accubation, supination, resupination, prostration, azimuth, plain, floor, platform, bowling green, cricket ground, croquet ground, croquet lawn, billiard table, terrace, estrade, esplanade, parterre, table land, plateau, ledge, butte, mesa (plain), level, spirit level, horizontal, level, even, plane, flat, flat as a billiard table, flat as a bowling green, alluvial, calm, calm as a mill pond, smooth, smooth as glass, recumbent, decumbent, procumbent, accumbent, lying, prone, supine, couchant, jacent, prostrate, recubant, horizontally, on one's back, on all fours, on its beam ends.
Flatness
N
flatness, smoothness, plane, level, plate, platter, table, tablet, slab, flat, plane, even, flush, scutiform, discoid, level, flat as a pancake, flat as a fluke, flat as a flounder, flat as a board, flat as my hand.