Thank″less, a. 1. Not acknowledging favors; not expressing thankfulness; unthankful; ungrateful.
That she may feel
How sharper than a serpent's tooth it is
To have a thankless child! Shak.
2. Not obtaining or deserving thanks; unacceptable; as, a thankless task.
To shepherd thankless, but by thieves that love the night allowed. Chapman.
— Thank″less‐ly (#), adv. — Thank″less‐ness, n.