in·grate
ˈinɡrāt/
noun
noun: ingrate; plural noun: ingrates
  1. 1.
    an ungrateful person.
adjective

literary
adjective: ingrate
  1. 1.
    ungrateful.
Origin
late Middle English (as an adjective): from Latin ingratus, from in- ‘not’ + gratus ‘grateful.’