根究

to investigate (sth) thoroughly / to get to the bottom of

root / basis / classifier for long slender objects, e.g. cigarettes, guitar strings / CL:條|条[tiao2] / radical (chemistry)

after all / to investigate / to study carefully / Taiwan pr. [jiu4]

(idiom) in the final analysis

lit. to examine roots and inquire at the base (idiom); to get to the bottom of sth

to get to the heart of the matter

erhua variant of 追根究底[zhui1 gen1 jiu1 di3]