Synonyms for Sag:

n.

decrease, drop, diminish, decline, dwindle, crater, shrink. boil over, cloud, boil, break down, clear, lop, boil up, boil away, slouch, atomize, bake, flop, bubble. cut, plunge, cutback, collapse, reduction, better, shrinkage. depression, pit, dip, sink, concavity, convex, basin, sinkhole, hollow. curve (noun)
bend.
decrease (noun)
drop.
depression (noun)
list, slump, distortion, sinkhole, fall, settling, cant, tilt, dip, sinking.
drop, decline (noun)
droop, fall, slump, depression, tilt, settling, sinkhole, list, hollow, sinking, basin, distortion, sink, slip, cant, dip, concavity.
sag (noun)
flag, sag down, droop, swag.

v.

curve (verb)
crook, hang, bend, round, hook, camber, bow, arch, swerve, sweep, curve.
droop (verb)
flop, fall off, drop, bend, dangle, hang, flag, bow, decline, swag, drop off, curve.
hang (verb)
loll, trail, drape, sway, droop, nod, bob, Draggle, dangle, swing.

Other synonyms:

sinkhole. concavity, pit. basin, slouch. depression, dip. flop. slip. decrease
drop off.
Other relevant words:
fall, cut, diminish, basin, swag, hollow, fall off, reduction, depression, sinkhole, sinking, settling, sink, decline, shrink, dwindle, flag, drop, sag down, distortion, slouch, pliant, flexible, flop, tilt, pit, dip, lop, cant, decrease, slump, list, plunge, concavity, slip.

Usage examples for sag

  1. Amazement made him sag down in his chair. – Slippy McGee, Sometimes Known as the Butterfly Man by Marie Conway Oemler
  2. No guide- ropes, nothing, and the water boiling at the sag of the log to your knees. – Smoke Bellew by Jack London
  3. At last one venturesome fellow struck boldly out and lit on it, only to feel it sway and sag and, with a shriek rivaling that of his predecessor, flapped up just in time to save himself, as he believed, from a terrific disaster. – Sigurd Our Golden Collie and Other Comrades of the Road by Katharine Lee Bates