Definition of "crusty"

No one was there. But there was a cloth spread upon the table that stood against the wall, and a cover was laid for one, with a crusty brown loaf and a bottle of wine beside the plate

1899, Kate Chopin, The Awakening

However kindly a friend may otherwise be, he soon turns crusty if asked to lend money.

1895, Marie Corelli, The Sorrows of Satan, page 12

Then somebody told a story about the Swedish Majesty's last sojourn in Norway. There, at a railway station, Oscar ran against a crusty old farmer who thought himself a lot better than a mere king and kept his hat on.

1922, Henry William Fischer, Abroad with Mark Twain and Eugene Field

Visitors to Maine often expect to find such colorful characters at every turn. In fact, Governor Angus King once said that if he could just strategically position a suitable crusty yet benign "Mainah" on the porch of every general store or end of every lobster wharf, giving people asking for directions the standard reply of "You can't get theyah from heyah," tourism revenue would triple.

2009, Earl Brechlin, Adventure Guide to Maine, page 65

Against the backdrop of muted stripes of color, Julieanne picked at her eyes’ crusties, and then combed her hair with the hand.

1999, Vinnie Hansen, Murder, Honey, Xlibris Corporation,, page 155

Jesus, how could I bear the sight of him—sleep crusties lodged in the corners of his rheumy eyes, a puff of chest hair cresting like meringue over the top of his V-neck sweater, khakis jacked up to his breastbone—when I was used to looking at the singularly lovely Isabella?

2003, Mary O'Connell, “Saint Anne”, in Living with Saints, Grove Press, page 209

I wiped the crusties from my eyes, threw on a sundress, and wandered out into the living room.

2005, Jeffrey Dinsmore, I, an Actress: The Autobiography of Karen Jamey, Contemporary Press, page 51

2010, Matthew Collin, Altered State: The Story of Ecstasy Culture and Acid House‎, page 202:Many of them, dressed in raggedy black combat gear, with haircuts that matched and mismatched punk, Rasta and Native American styles - a look which would later be codified as 'crustie' - began to join the travellers on the road. This influx from the cities changed the travelling scene, and after the Battle of the Beanfield, sections of the downcast and disillusioned travelling community began to seek oblivion through Special Brew superlager or even heroin as the dream of rural liberation turned sour.

1998, Simon Reynolds, Energy Flash, Soft Skull Press, published 2012, page 135:The Spirals are part of the crossover between the rave scene and the ‘crusty’ subculture—crusties being squat-dwelling anarcho-hippy-punk types named after their matted dreadlocks and post-apocalyptic garb.

The predictable complaints began as soon as Extinction Rebellion launched its fortnight of protest in London, part of an international campaign of civil disobedience in as many as 60 cities worldwide. Politicians have moaned that the police are being too passive, and Boris Johnson, Britain’s prime minister, labelled the protesters – who include a former Metropolitan police detective – “uncooperative crusties”.

2019 October 10, “The Guardian view on the Extinction Rebellion protests: of course they’re an inconvenience”, in The Guardian‎