chat up

verb

1. to talk flirtatiously to (a person), esp with the intention of seducing him or her

2. to talk persuasively to (a person), esp with an ulterior motive

Idioms and Phrases

Talk flirtatiously to, as in Leave it to Charlie to chat up the girls . This usage is mostly but not entirely British. [Late 1800s]

Engage in light, friendly talk, as in He was soon chatting up all the board members . [Mid-1900s]