Comparative form of narrow: more narrow(adjective)
One who, or that which, narrows.(noun)
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Use "narrower" in a sentence
"The main course of this river, not over twenty yards at its widest part, usually much narrower, is navigable for canoas for half a mile to a point where the land is dry and from which the town lies yet another mile distant."
"The eyes not large but big and bright, and the chin narrower, giving a triangular shape to the face."
"Playing in narrower release, the Will Ferrell-produced teen comedy "The Virginity Hit" flopped with just $300,000."