"Haven't I told you he's not going?" he hissed. "He's going to Stonewall High and he'll be grateful for it. I've read those letters and he needs all sorts of rubbish –– spell books and wands and ––"
"If he wants ter go, a great Muggle like you won't stop him," growled Hagrid. "Stop Lily an' James Potter's son goin' ter Hogwarts! Yer mad. His name's been down ever since he was born. He's off ter the finest school of witchcraft and wizardry in the world. Seven years there and he won't know himself. He'll be with youngsters of his own sort, fer a change, an' he'll be under the greatest headmaster Hogwarts ever had Albus Dumbled––"
"I AM NOT PAYING FOR SOME CRACKPOT OLD FOOL TO TEACH HIM MAGIC TRICKS!" yelled Uncle Vernon. (Harry Potter and the Sorcerer's Stone)
Old is used as an intensifier, say these websites: Webster's #5; Wiktionary #12. So I guess the example's old has the meaning after an adjective crackpot. But I’m not sure, ‘cause the websites seem to kind of restrict the boundary of the use. Can old be used as an intensifier after all sorts of adjectives or adjective phrases?