Com*bust" (?), a. [L. combustus, p. p. of comburere to burn up; com- + burere (only in comp.), of uncertain origin; cf. bustum funeral pyre, prurire to itch, pruna a live coal, Gr. pyrso`s firebrand, Skr. plush to burn.] 1. Burnt; consumed. [Obs.] Chaucer.

2. (Astron.) So near the sun as to be obscured or eclipsed by his light, as the moon or planets when not more than eight degrees and a half from the sun. [Obs.]

Planets that are oft combust.
Milton.