鑽心蟲

boring insect / snout moth's larva (Aphomia gullaris or Plodia interpuncuella or Heliothus armigera etc), major agricultural pest

to drill / to bore / to get into / to make one's way into / to enter (a hole) / to thread one's way through / to study intensively / to dig into / to curry favor for personal gain

an auger / diamond

to sneak in / to infiltrate / to be piercingly painful / to be unbearable (of pain, itch etc)

heart / mind / intention / center / core / CL:顆|颗[ke1],個|个[ge4]

lower form of animal life, including insects, insect larvae, worms and similar creatures / CL:條|条[tiao2],隻|只[zhi1] / (fig.) person with a particular undesirable characteristic