偷偷 | tōu tōu | stealthily / secretly / covertly / furtively / on the sly | |
阉然 | yān rán | covertly / secretly | |
暗喜 | àn xǐ | hidden smile / smirk / to rejoice covertly / secret satisfaction concerning one's evil plans | |
明争暗斗 | míng zhēng àn dòu | to fight openly and maneuver covertly (idiom) |