ἐν πέτροισι πέτρον ἐκτρίβων → by grinding stone against stones
weak: P. and V. ἀσθενής, V. ἄναρθρος, ὑγρός, ἄναλκις.
Met., remiss: Ar. and P. μαλακός, Ar. and V. μαλθακός.
