ungrateful
1. [ adjective ] not feeling or showing gratitude
Synonyms: unthankful thankless
Examples:

"ungrateful heirs" "How sharper than a serpent's tooth it is / To have a thankless child!"- Shakespeare

Related terms: grateful unappreciative
2. [ adjective ] disagreeable
Examples:

"I will not perform the ungrateful task of comparing cases of failure"- Abraham Lincoln

Related terms: unpleasant
Similar spelling:   ungratefully
  ungraceful
  ungracefully
  uncrate
  ungratified
  ungreased
  ungrasped
  uncreased