切入

to cut into / to incise / to penetrate deeply into (a topic, area etc) / cut (offensive moves in basketball)

to enter / to go into / to join / to become a member of / to confirm or agree with / abbr. for 入聲|入声[ru4 sheng1]

to cut / to slice / tangent (math)

definitely / absolutely (not) / (scoffing or dismissive interjection) Yeah, right. / Tut! / to grind / close to / eager / to correspond to / see also 反切[fan3 qie4]