narrow has 12 distinct synonyms spread across 6 of its 10 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its 2 recorded opposites are wide, widen.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
lacking tolerance or flexibility or breadth of view
“a brilliant but narrow-minded judge”
very limited in degree
“won by a narrow margin”
characterized by painstaking care and detailed examination
“a minute inspection of the grounds”
make or become more narrow or restricted
“The selection was narrowed”
define clearly
“I cannot narrow down the rules for this game”
become more focused on an area of activity or field of study
“She specializes in Near Eastern history”
become tight or as if tight
“Her throat constricted”
a narrow strait connecting two bodies of water
1 of the 10 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for narrow.
Synonyms, antonyms and the broader and narrower relations for narrow come from Princeton University’s WordNet. Full sources and licences.