Unfair competition (competencia desleal) is treated as a separate area of study under Spanish business law (Derecho mercantil) and is regulated in a specific law (Ley 3/1991 de Competencia Desleal, as amended). In other jurisdictions, unfair commercial practices may be addressed in competition or consumer protection laws, such as the EU’s Unfair Consumer Practices Directive 29/2005 or the US Revised Uniform Deceptive Trade Practices Act and similar state laws. This glossary contains 25 of the most frequently-used terms in Spanish unfair competition law with possible English renderings.

• acto de comparación–act of comparison
• acto de competencia desleal–act of unfair competition
• acto de confusión–act of confusion (capable of creating confusion with a competitor’s products, services or establishment)
• acto de denigración–act of disparagement
• acto de engaño–act of deception
• acto de imitación sistemática–act of systematic imitation (of a competitor’s products or services)
• acto desleal; ilícito concurrencial–act of unfair competition
• aprovechamiento indebido de la reputación ajena–unduly trading on another’s business goodwill (or) reputation
• competencia desleal; concurrencia desleal–unfair competition
• competencia ilícita–unlawful competition
• competencia parasitaria–parasitic competition
• conducta anticompetitiva; conducta contraria a la competencia; conducta restrictiva de la competencia–anticompetitive conduct; conduct in restraint of trade
• denigración–disparagement
• Derecho de la competencia desleal–unfair competition law
• deslealtad al competidor—unfair competition practices
• deslealtad al consumidor–unfair consumer practices
• deslealtad de mercado–unfair market practices
• discriminación en materia de precios–price discrimination; discriminatory pricing
• engaño por silencio–deception by silence
• explotación de la reputación ajena–exploiting another’s reputation
• Ley de Competencia Desleal–Unfair Competition Act
• libertad de elección del consumidor—consumer’s freedom of choice
• omisión engañosa–deceptive omission
• ventas a pérdida--dumping
• violación de secretos comerciales–misappropriation of trade secrets

Source: Rebecca Jowers. Diccionario de términos y conceptos jurídicos español-inglés. Tirant lo Blanch, 2023.