General Synonyms:
* Poor
* Inferior
* Second-rate
* Substandard
* Cheap
* Flimsy
* Unreliable
* Unsatisfactory
* Defective
* Faulty
Synonyms emphasizing poor quality:
* Crappy (informal)
* Lousy (informal)
* Rubbish (British)
* Trashy
* Bunk (informal)
* Junk
* Inferior
* Mediocre
Synonyms emphasizing poor workmanship:
* Sloppy
* Careless
* Haphazard
* Clumsy
* Unprofessional
* Amateurish
Synonyms emphasizing dishonesty or deceitfulness:
* Sham
* Fake
* Phony
* Deceptive
* Fraudulent
* Bogus
Synonyms emphasizing old or worn-out:
* Ragged
* Tattered
* Faded
* Dilapidated
* Run-down
The best synonym to use will depend on the specific context in which you're using the word. For example, if you're talking about a poorly made product, you might use "inferior" or "substandard." If you're talking about someone's work ethic, you might use "sloppy" or "careless."