Yields and strays — into such transgression? (6,3)
I believe the answer is:
Here is my best explanation:
'such transgression?' is the definition.
'deadly sin' can be an answer for 'transgression?' (deadly sin is a kind of transgression). I am not sure about the 'such' bit.
'yields and strays' is the subsidiary indication.
'strays' indicates anagramming the letters.
'yieldsand' with letters rearranged gives 'deadlysin'.
'into' is the link.
(Other definitions for deadly sin that I've seen before include "not good - bad", "It's one of seven, gluttony say", "Anger, say", "greed, or lust", "Lethal lapse like pride, gluttony or envy", "eg lust", "Anger, covetousness, envy, gluttony, lust, pride or sloth", "Eg, lust or gluttony", "envy for example" and "Eg, lust or pride".)