Synonyms for Grinding:

adj.

abrasive (adjective)
eroding, crushing, bone-crushing, Crumbling, grating, shivering, milling, Granulating, Pulverizing, Powdering, smashing, Disintegrating, rubbing, scraping, Crunching.
chafing (adjective)
wearing, Resisting, rasping, scrubbing, chafing, scraping, friction, rubbing.
difficult (adjective)
demanding, toilsome, complex, cantankerous, tough, severe, rough, arduous, burdensome, onerous, wearing, harsh, hard, finicky, adverse, rugged, fussy, tricky, thorny, wearying, complicated, cumbersome, wearisome, troublesome, uphill, strenuous, stressful, oppressive, knotty, trying, laborious, contrary, formidable, bothersome, difficult, tight, ticklish.
severe (adjective)
severe.

n.

unspeakable, sadly, utter, downright, sorry, excruciating, hopelessly, utterly, such as it is, thorough. two-tone, staccato, broken, inaudible, rhythmic. abrasive (noun)
shivering, wearing away, smashing, reducing to dust, bone-crushing, fricative, triturative, milling, eroding, crushing, Crumbling, Chopping, Powdering, Pulverizing, Disintegrating, Granulating, Crunching, cracking, splintering, comminutive.
friction (noun)
friction, resistance, abrasion.
grinding (noun)
attrition, detrition, abrasion.

v.

chafing (verb)
grating, disturbing, scraping, rubbing, aggravating, irritating, chafing, scrubbing, Abrading, Harassing, Resisting, wearing, Fretting, rasping.
smoothing (verb)
Burnishing, leveling, Planing, Smoothing, Glazing, Glossing, evening, polishing, Slicking, Sanding, Flattening.

Other synonyms:

inaudible. staccato, two-tone. broken. Other relevant words:
detrition, smashing, Crumbling, chafing, excruciating, crushing, attrition, Powdering, Crunching, wearing away, Disintegrating, milling, two-tone.

Usage examples for grinding

  1. That worthy affected not to know him, and went on grinding a big saw. – Put Yourself in His Place by Charles Reade
  2. No more grinding fear, no more " bad days," no more wishing to die, no more nervous prostration. – In Times Like These by Nellie L. McClung
  3. Now it seems to me that I ought to begin this tale with the reason why some of us Boston lads decided it might be possible for us to work in behalf of the Cause, and in order to do that I must hark back to what has been done these two years past to us of Boston by the king, and those hangers on of his who counted on grinding us into the dust as if we were made of baser stuff than they. – The Minute Boys of Boston by James Otis