to carry on intensive and thorough research for data, information, or the like; investigate

to delve into the issue of prison reform.

Archaic . to dig, as with a spade.

Archaic . to dig; excavate.

verb

burrow , dig , dredge , examine , excavate , explore , ferret out * , go into , gouge out , inquire , investigate , jump into , leave no stone unturned , look into , probe , prospect , ransack , really get into , research , rummage , scoop out , search , seek , shovel , sift , spade , trowel , turn inside out , unearth , reconnoiter , scout , grub , scoop , mine