Not feeling or showing gratitude:
— How sharper than a serpent's tooth it is / To have a thankless child!.

synoniemen: ungrateful, unthankful.

Roget 830: causing pain, hurting etc. v.; hurtful etc. (bad) 649; painful; dolorific^†, dolorous; unpleasant; unpleasing, displeasing; disagreeable, unpalatable, bitter, distasteful; uninviting; unwelcome; undesirable, undesired; obnoxious; unacceptable, unpopular, thankless.    unsatisfactory, untoward, unlucky, uncomfortable.    distressing; afflicting, afflictive; joyless, cheerless, comfortless; dismal, disheartening; depressing, depressive; dreary, melancholy, grievous, piteous; woeful, rueful, mournful, deplorable, pitiable, lamentable; sad, affecting, touching, pathetic.    irritating, provoking, stinging, annoying, aggravating, mortifying, galling; unaccommodating, invidious, vexatious; troublesome, tiresome, irksome, wearisome; plaguing, plaguy^†; awkward.    importunate; teasing, pestering, bothering, harassing, worrying, tormenting, carking.    intolerable, insufferable, insupportable; unbearable, unendurable; past bearing; not to be borne, not to be endured; more than flesh and blood can bear; enough to drive one mad, enough to provoke a saint, enough to make a parson swear, enough to gag a maggot.    shocking, terrific, grim, appalling, crushing; dreadful, fearful, frightful; thrilling, tremendous, dire; heart-breaking, heart-rending, heart-wounding, heart-corroding, heart-sickening; harrowing, rending.    odious, hateful, execrable, repulsive, repellent, abhorrent; horrid, horrible, horrific, horrifying; offensive.    nauseous, nauseating; disgusting, sickening, revolting; nasty; loathsome, loathful^†; fulsome; vile etc. (bad) 649; hideous etc. 846.    sharp, acute, sore, severe, grave, hard, harsh, cruel, biting, caustic; cutting, corroding, consuming, racking, excruciating, searching, grinding, grating, agonizing; envenomed; catheretic^†, pyrotic [Med.].    ruinous, disastrous, calamitous, tragical; desolating, withering; burdensome, onerous, oppressive; cumbrous, cumbersome.    ... meer laten zien

Roget 917: ungrateful, unmindful, unthankful; thankless, ingrate, wanting in gratitude, insensible of benefits.    forgotten; unacknowledged, unthanked^†, unrequited, unrewarded; ill-requited.   

Not likely to be rewarded:
— Grading papers is a thankless task.

synoniemen: unappreciated, ungratifying.