Verbals in -τός, -τή, -τόν either (1) have the meaning of a perfect passive participle, as κρυπτός
a. Usually passive in meaning are verbals from deponent verbs, as μι_μητός
b. Usually active in meaning are compounds derived from transitive active verbs; but some intransitive verbs make active verbals, as ῥυτός
c. Many are active or passive, others only active: μεμπτός
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].