† deleteryadj.n.

Etymology: < post-classical Latin deleterius noxious, poisonous (1561 in the passage translated in quot. 1576 at sense A. 1; also as deletorius (1576 or earlier)) < ancient Greek δηλητήριος noxious, poisonous < δηλεῖσθαι to hurt, of unknown origin + -τήριος , suffix forming adjectives (probably after σωτήριος that saves or delivers; compare δηλήτηρ destroyer, in an isolated attestation). Compare deleterial adj., deleterious adj., and later deletory adj.Compare Middle French deletere , French délétère (1370), Spanish deleterio (end of the 16th cent.). With use as noun compare post-classical Latin deleterion (5th cent.), ancient Greek δηλητήριον , both in the sense ‘poison’. Specific forms. In the 17th cent. often mistakenly viewed as a derivative of classical Latin dēlēre (past participial stem dēlēt- ) to blot out, efface, destroy completely (see delete v.), and consequently frequently spelt deletory (as if < classical Latin dēlēt- + -ory suffix²; compare deletory adj.) and used in the senses ‘destroying completely’, ‘something that destroys completely’; compare senses A. 2, B. 2. With the form deletary perhaps compare -ary suffix². Pronunciation. N.E.D. (1895) gives the pronunciation as (de·lĭtĕri) /ˈdɛlɪtərɪ/, and comments: ‘By Butler stressed ˈdeletery; but generally perhaps deˈletery’.