threadbare

Short definition from Wiktionary

Adjective

1. 1
   Of cloth, clothing, furnishings, etc.: frayed and worn to an extent that the nap is damaged and the warp and weft threads show; shabby, worn-out.
2. 2
   In poor condition; damaged, shabby; also, poorly equipped or provided for, inadequate, meagre, scanty.
3. 3
   Of an argument, excuse, etc.: used so often that it is no longer effective or interesting; banal, clichéd, trite.
4. 4
   An argument or assertion with little in the way of substance or supporting evidence.
5. 5
   Of a person: wearing clothes of threadbare (sense 1) material; hence, impoverished, poor.