to adjust one's speech and behavior to suit the audience or situation; versatile in communication

他在生意场上见人说人话，见鬼说鬼话，应付自如。

to be insincere or hypocritical; saying different things to different people to serve one's own ends

他是个见人说人话，见鬼说鬼话的伪君子，不可信任。