luculent

1. (now rare) Shining, brilliant.
2. (obsolete) Of language, speeches etc: lucid, brilliantly clear.
   • 1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps, OCLC 54573970 ↗:

     , I.iv.1:

     Cleombrotus Ambraciotes persuaded I know not how many hundreds of his auditors, by a luculent oration he made of the miseries of this, and happiness of that other life, to precipitate themselves […].