Noviro
卧底
Simplified 卧底
Traditional 臥底
Pinyin wò dǐ
Definition to hide (as an undercover agent); an insider (in a gang of thieves); a mole
他是个卧底，别说话
Tā shì gè wòdǐ, bié shuōhuà
He's an undercover agent, don't speak
You might also see
底
dǐ
bottom; base; background; foundation; copy (of a manuscript or receipt etc.) kept as a record; (suffix) end of a year or month; (math.) radix; base (abbr. for 底数)
HSK4
到底
dào dǐ
finally; in the end; when all is said and done; after all; to the end; to the last
HSK3
底下
dǐ xia
the location below sth; afterwards
HSK3
彻底
chè dǐ
thorough; thoroughly; complete
HSK4
月底
yuè dǐ
end of the month
HSK4
海底
hǎi dǐ
seabed; seafloor; bottom of the ocean
HSK6
底线
dǐ xiàn
bottom line; the limit of what one is prepared to accept; (sports) baseline; (sewing) under thread; spy; informer; plant
垫底
diàn dǐ
to put sth on the bottom; to eat sth to tide oneself over until mealtime; to lay the foundation; to come last in the rankings