Someone or somewhere down-at-heel looks tired, shabby, and not well cared for, because there is not enough money. A down-at-heel hotel has worn carpets; a down-at-heel person may wear old shoes and a tired coat. The picture behind it is a shoe whose heel is worn right down — a sign you cannot buy new ones. Though actually, people now use it as much for streets, shops, and buildings as for people, and it feels a little old and British; younger speakers often just say run-down or shabby. Said about a person it can sting, so kind teachers use it carefully. You will also see down at heel and down-at-the-heels.