narrowest
nar-row-est
adjective
Having the least width or scope; most restricted in space or extent.
"This is the narrowest path to the summit."
Thesaurus
Synonyms: narrow, specialise, specialize, narrow down, constringe, constrict, marginal, bare, dogmatical, petty, closed-minded, self-opinionated
Antonyms: branch out, broad, broad-minded, broaden, diversify, wide, widen