Straight and Narrow
WordNet

noun


(1)   The way of proper and honest behavior
"He taught his children to keep strictly to the straight and narrow"
WiktionaryText

Etymology


Probably "strait and narrow," from Matthew 7:14

Adverb



  1. honest; proceeding according to rules and plans
    The project would seriously go down the pan if Mrs. Foster weren't here to keep it on the straight and narrow.
 
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