出自肺腑

from the bottom of one's heart (idiom)

to go out / to come out / to occur / to produce / to go beyond / to rise / to put forth / to happen / (used after a verb to indicate an outward direction or a positive result) / classifier for dramas, plays, operas etc

variant of 出[chu1] (classifier for plays or chapters of classical novels)

to come from

self / oneself / from / since / naturally / surely

lung / CL:個|个[ge4]

bottom of the heart (fig.)

internal organs