noun

• (sometimes attributive) The light reflected from the Moon.
  "If you will patiently dance in our round / And see our moonlight revels, go with us; / If not, shun me, and I will spare your haunts."

verb

• (by extension) To engage in an activity other than what one is known for.
  "Mr. Katzenberg, who moonlights as a top Biden official and has worked with Mr. Clooney on philanthropy for decades, reached out to him to see if there was an off-ramp, according to three people familiar with the matter."
• (by extension, of an inanimate object) To perform a secondary function substantially different from its supposed primary function, as in protein moonlighting.
• (British, dated) To carry out undeclared work.