1. Not consistent; showing inconsistency; irreconcilable; discordant; at variance, especially. As regards character, sentiment, or action; incompatible; incongruous; contradictory. Compositions of this nature . . . Show that wisdom and virtue are far from being inconsistent with politeness and good humor. (Addison)
2. Not exhibiting uniformity of sentiment, steadiness to principle, etc.; unequal; fickle; changeable. Ah, how unjust to nature, and himself, Is thoughtless, thankless, inconsistent man. (Young)
Synonym: incompatible, incongruous, irreconcilable, discordant, repugnant, contradictory.
inconsistent, incongruous, incompatible. Things are incongruous when they are not suited to each other, so that their union is unbecoming; inconsistent when they are opposed to each other, so as render it improper or wrong; incompatible when they can not coexist, and it is therefore impossible to unite them. Habitual levity of mind is incongruous with the profession of a clergyman; it is inconsistent with his ordination vows; it is incompatible with his permanent usefulness. Incongruity attaches to the modes and qualities of things; incompatibility attaches to their essential attributes; inconsistency attaches to the actions, sentiments, etc, of men.
Origin: Pref. In- not – consistent: cf. F. Inconsistant.