What does faulty mean?
Faulty is an adjective describing something that contains a defect or flaw — a piece of equipment that does not work as intended, a structure built below standard, or an argument undermined by error. It is most frequently encountered in technical and consumer contexts: faulty wiring causes fires, faulty parts trigger vehicle recalls, and faulty appliances are returned under warranty. The word also extends naturally to abstract domains, as in faulty logic, faulty reasoning, or a faulty memory, where it indicates that the underlying process or information is unsound rather than merely imperfect. Connotatively, faulty is neutral to mildly negative; it identifies a problem without assigning blame, which makes it useful in legal and investigative language where precision matters more than accusation. Derived from the noun 'fault' with the adjectival suffix '-y', it shares deep roots with words like fallacy and fallible, all tracing back to the Latin verb fallere, meaning to deceive or disappoint — fittingly, for a word whose business is identifying what has failed us.
Containing a defect or flaw; not working correctly or not made properly.
"The fire was caused by faulty electrical wiring."
Frequently used in technical, legal, and consumer-protection contexts.
Based on or containing an error or flaw, as of reasoning, judgment, or information.
"The study's conclusions were dismissed because of its faulty methodology."
Often applied abstractly to logic, assumptions, data, or memory.
'Faulty' and 'fallacy' are cousins — both descend from the Latin verb fallere, 'to deceive,' so a faulty argument is literally one that deceives you.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of faulty
Faulty derives from the English noun 'fault' combined with the adjectival suffix '-y'. 'Fault' itself entered Middle English in the medieval period from Old French 'faute' (itself a variant of 'defaute'), ultimately stemming from the Latin verb fallere, meaning to deceive or disappoint. This same Latin root gave English 'fallacy', 'fallible', and 'failure', making 'faulty' part of a large family of words concerned with deception and shortcoming. The adjective 'faulty' was well established by the early modern period and has long been used of both physical defects and errors of reasoning.
Related word forms
How faulty is actually used
Neutral-to-negative connotation; common in technical, legal, and consumer contexts (e.g. product recalls, liability claims). When applied to reasoning or memory ('faulty logic', 'faulty memory'), it signals error without necessarily implying bad intent.
Easily confused with faulty
A faux pas is a social blunder or breach of etiquette, whereas faulty describes something defective in function, structure, or logic.