From principle +‎ -ed.

• IPA^(key): /ˈpɹɪnsɪpəld/, /ˈpɹɪnsəpəld/

principled (comparative more principled, superlative most principled)

1. Based on, having, or manifesting principles
   • 1692, Roger L’Estrange, “ (please specify the fable number.) (please specify the name of the fable.)”, in Fables, of Æsop and Other Eminent Mythologists:[…], London: […] R[ichard] Sare,[…], →OCLC:

     Governors had need be well principled.

   While most of these efforts have focused on compressing the uplink, none of them provide a principled solution to compressing the downlink.

   1. strongly adhering to, or heedful of, guiding beliefs or moral rules

• unprincipled

principled

1. simple past and past participle of principle