undercover
un.der.cov.er \-'k*v-*r\ aj : acting or executed in secret; specif :
employed or engaged in s pying or secret investigation {~ agent}
Webster's English Dictionaryun.der.cov.er \-'k*v-*r\ aj : acting or executed in secret; specif :
employed or engaged in s pying or secret investigation {~ agent}