thankless   (TTS Sound)

The adj thankless has 2 senses

• ungrateful, thankless, unthankful -- (not feeling or showing gratitude; "ungrateful heirs"; "How sharper than a serpent's tooth it is / To have a thankless child!"- Shakespeare)


• thankless, unappreciated, ungratifying -- (not likely to be rewarded; "grading papers is a thankless task")