Synonyms for Principle:

adj.

instrumental (adjective)
helpful, essential, useful, valuable, instrumental, effectual.

n.

commitment, source, origin, ideal, law. gloss, explanation, outline, system, interpretation, clarification. good, respectability, fundamental, purity, propriety, right, universal, virtue, decency, modesty, order, goodness. character, strong, integrity, fiber, honesty. belief (noun)
credence, tenet, conviction, postulate, philosophy, thought, trust, view, certitude, dogma, faith, creed.
cognition (noun)
rule.
idea (noun)
perception, observation, supposition, theory, plan, conception, image, brainstorm, reflection, ideation, notion, design, inspiration, vision, inkling.
instruction (noun)
instruction, moral, directive, byword, edict, axiom, catchword, rule, teaching, saw, credo, proverb, saying, precept, policy, motto, adage, code, ordinance, dictum, doctrine, bidding.
in theory (noun)
in essence, theoretically, ideally.
law, standard (noun)
dictum, dogma, axiom, assumption, fundamental, source, origin, rule, postulate, basis, theorem, doctrine, precept.
principle (noun)
rationale, rule, precept.
topic (noun)
contention, premise, belief, matter, conjecture, opinion, theme, theorem, point, text, assertion, statement, topic, subject, concept, hypothesis, postulation, motif, essay, argument, query, exposition, issue, dissertation, paradigm, inference, question, thesis, consideration, problem, basis, idea, presumption, assumption, position.

Other synonyms:

clarification, interpretation, ideal, commitment, explanation. integrity. fiber, outline. gloss, universal. character. law. integrity
honesty.
Other relevant words:
gloss, character, integrity, universal, clarification, commitment, in essence, strong, origin, right, interpretation, source, explanation, goodness, ideal, respectability, good, honesty, purity, rationale, system, order, modesty, fundamental, virtue, outline, theoretically, ideally, decency, propriety, law, fiber.

Usage examples for principle

  1. " That is the principle we use in making it a weapon. – Invaders from the Infinite by John Wood Campbell
  2. I come on principle and I shall look at him through that eye, and no other. – Sweet Cicely Or Josiah Allen as a Politician by Josiah Allen's Wife (Marietta Holley)
  3. Well, that is exactly the principle of the flying machine. – American Men of Mind by Burton E. Stevenson