Adjective : an unthankful task.    From Dictionary.com. 

Highest; for he is kind to the unthankful and evil.    From Wordnik.com.  [The New Testament of our Lord and Savior Jesus Christ. The common English version, corrected by the final committee of the American Bible Union.] Reference

This is what one gets by serving unthankful people.    From Wordnik.com.  [The Arabian Nights Entertainments - Volume 01] Reference

So unthankful, so odious is the task of reforming in.    From Wordnik.com.  [Travels in Morocco] Reference

Politics isn't glamorous, it's hard, unthankful work.    From Wordnik.com.  [Charles Karel Bouley: Real Life vs. Hollywood] Reference

You have to enjoy the journey, it's unthankful not to.    From Wordnik.com.  [The Reagans and the Kennedys] Reference

But whether there be or not, let us not be unthankful to.    From Wordnik.com.  [Chronicle and Romance (The Harvard Classics Series)] Reference

W.A. - I am an unthankful, ungrateful dog, that is true.    From Wordnik.com.  [The Further Adventures Of Robinson Crusoe]

Wow ... wee we can be some unthankful individuals at times.    From Wordnik.com.  ["The Rainest Month of June"] Reference

We see it in His not withholding His abundance even from the unthankful.    From Wordnik.com.  [The Atlantic Monthly, Volume 04, No. 26, December, 1859] Reference

Magazine interviews make her sound like a snob or unthankful or whatever.    From Wordnik.com.  [Twilight Lexicon » Kristen’s Appearance on Jimmy Kimmel] Reference

"Surely, to confer a favor on the unthankful, is like pouring water on sand.".    From Wordnik.com.  [The Knight of the Golden Melice A Historical Romance] Reference

Still I am but a dwarf in growth, yet will I not be unthankful for what I am.    From Wordnik.com.  [Religion in Earnest A Memorial of Mrs. Mary Lyth, of York] Reference

Our Lord can be patient with the impatient: He can be "kind to the unthankful.".    From Wordnik.com.  [My Daily Meditation for the Circling Year] Reference

How unthankful can You be by john riggs on Wednesday, Jan 9, 2008 at 7: 26: 09 AM.    From Wordnik.com.  [The Issues The Candidates Won't Touch (Part I)] Reference

The miracles no longer amazed him, but he had not become indifferent or unthankful.    From Wordnik.com.  [The Yoke A Romance of the Days when the Lord Redeemed the Children of Israel from the Bondage of Egypt] Reference

‘Then you are an ungrateful, unworthy, demd unthankful little fairy,’ said Mr Mantalini.    From Wordnik.com.  [Nicholas Nickleby] Reference

Reckon your deliverance under this head of operations, and I hope you will not be unthankful.    From Wordnik.com.  [The Sermons of John Owen] Reference

Do they not avert the unthankful task of carting away dozens of barrow loads of superfluous fruit?.    From Wordnik.com.  [Tropic Days] Reference

He shall entertain and feed, and give drink to the unthankful, and moreover he shall hear bitter words.    From Wordnik.com.  [The Bible, Douay-Rheims, Book 26: Ecclesiasticus The Challoner Revision] Reference

Do you know how hard and unthankful a task it is to write thise fake few stories for newspaper movie props?.    From Wordnik.com.  [Feeling Listless - "Taking the credit for your second symphony."] Reference

I knew that intruding into the private affairs of ducal and princely houses is often a most unthankful business.    From Wordnik.com.  [The Secrets of the German War Office] Reference

False to the sacred honor of our bed, O most unthankful for those many kisses … "Please, Niko, take me to Sicily!".    From Wordnik.com.  [The Mask of Apollo]

I know, I confess to Thee, O Lord, and with me there knows and blesses Thee, whoso is not unthankful to assure Truth.    From Wordnik.com.  [The Confessions] Reference

A sinner attributeth to himself the goods of his surety: and he that is of an unthankful mind will leave him that delivered him.    From Wordnik.com.  [The Bible, Douay-Rheims, Book 26: Ecclesiasticus The Challoner Revision] Reference

They each receive a pint of excellent soup and an unlimited quantity of bread for dinner; but they are discontented and unthankful.    From Wordnik.com.  [The Englishwoman in America] Reference

These favoured but unthankful people were not taken at their word; after the first refusal, another and more urgent invitation is sent.    From Wordnik.com.  [The Parables of Our Lord] Reference

People could quickly rush to judge me as unthankful.    From Wordnik.com.  [Economics Roundtable] Reference

Patient laborer, be strong; see how I toiled for the unthankful and the merciless.    From Wordnik.com.  [Blogotional] Reference

He is full of your praises, so you have not sowed your goodness in unthankful ground.    From Wordnik.com.  [The Letters of Horace Walpole, Earl of Orford — Volume 2] Reference