principled

1. 1
   adjective

   Strongly committed to one's guiding beliefs or moral rules, and careful to act in line with them even when it is costly.

   A principled negotiator, she walked away rather than accept a corrupt deal.

   Voters respected the senator as a principled opponent of the policy.

   Similarethical, honorable, upright, scrupulous, moral

   Oppositeunprincipled, unscrupulous, corrupt, dishonorable

   Note

   Here the principles are moral, and the word praises a person or the stand they take. That sets it apart from the broader rule-based meaning: a principled method only has to be consistent, while a principled negotiator holds to conscience at some cost. To tell them apart, look at the noun. With a person or an opponent, read the moral sense; with a method or solution, read the methodical one.

2. 2
   adjective

   Based on, having, or expressing a coherent set of underlying principles rather than scattered, one-off choices.

   The reform rested on a principled framework rather than political convenience.

   Scientists value a principled method for selecting data samples.

   Similarsystematic, coherent, consistent, rigorous

   Oppositearbitrary, haphazard

   Note

   In older English the word described people furnished with principles. Roger L'Estrange in 1692 writes that "governors had need be well principled," with well in front, as in well read or well bred. Today it is at home in research and technical prose. There a principled solution or method follows from a stated general rule, and its natural opposite is a one-off, ad hoc fix.

3. 3
   verb

   Simple past and past participle of principle.

   Note

   The verb behind this form is transitive: one principles someone, fixing them in a tenet or rule of conduct. It is usually followed by in, as in principled in the faith. In the passive the participle shades into the adjective, and "well principled" in the older person sense sits right on that line.

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