1800, William Cowper, The Task, Book VI: "The Winter Walk at Noon", Poems, J. Johnson, page 232,
No foe to man / Lurks in the ſerpent now: the mother ſees, / And ſmiles to ſee, her infant's playful hand / Stretch'd forth to dally with the creſted worm, / To ſtroke his azure neck, or to receive / The lambent homage of his arrowy tongue.
Glowing or luminous, but lacking heat.
The lambent glow of fireflies delighted the children.
[W]hile I held my son, in the short space
Betwixt our kisses and our last embrace;
Strange to relate, from young Iülus’ head
A lambent flame arose, which gently spread
Around his brows, and on his temples fed.
1839, Johann Wolfgang von Goethe, Jonathan Birch (translator), Faust: A Tragedy, Black and Armstrong, page 127,
The Witch, with much ceremony, fills the basin. As FAUST is about to raise it to his lips, it emits a clear flame.
MEPHISTOPHELES. Quick! quickly down with it!—no breathing time allowed! […] And does a lambent flame prevent thee quaff?
(figuratively) Exhibiting lightness or brilliance of wit; clever or witty without unkindness.