From WordNet (r) 3.0 (2006) [wn]:
moonlight
n 1: the light of the Moon; "moonlight is the smuggler's enemy";
"the Moon was bright enough to read by" [syn: moonlight,
moonshine, Moon]
v 1: work a second job, usually after hours; "The law student is
moonlighting as a taxi driver"
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Moonlight \Moon`light`\ (m[=oo]n"l[imac]t`), n.
The light of the moon. -- a. Occurring during or by
moonlight; characterized by moonlight.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Moonlight \Moon"light`\ (m[=oo]n"l[imac]t`), v. i.
to work at a second job in addition to one's main occupation;
-- often done at night.
[PJC]