Crusty means having a hard dry outer layer. Crusty bread, a crusty loaf, crusty round the edges.
Of bread it is a compliment: a crusty loaf has a crackling shell over a soft inside, which is what a hot oven and steam produce. Of anything else it usually means dried and unpleasant. Of a person it means irritable and gruff — a crusty old colonel — which is a fond insult more than a real complaint. Note crust; and the upper crust, meaning the upper class.
1adjectivecrustyHaving a hard dry outer layer.
“We bought a crusty loaf still warm from the baker's oven.”
2adjectiveirritableIrritable and gruff, of a person.
“The crusty old caretaker shouted at anyone who walked on his grass.”
crusty is a quality of hardness.
Crust plus -y, from Latin crusta, a shell or rind. Crustacean and encrust come from the same shell.
Middle English
crusty
English, today
crusty
From Middle English crusty, from und + cruste. From Middle English crusty, equivalent to crust + y.
Etymology from Wiktionary, CC BY-SA