(transitive) To tread again, to walk along again, to follow a path again.

(sometimes figuratively) A return over ground previously covered; a retraversal or repetition.

Delayed; delayed in development, hindered; impeded. / (psychology, now offensive, dated) Having mental retardation; mentally deficient or underdeveloped.

simple past tense and past participle of retard

Hard to ignite; not supporting or conveying flame.

A substance used to make an object flameproof.

Hard to ignite; not flammable.

A substance that makes an object resistant to burning.

(intransitive) To do something harmful or negative to get revenge for some harm; to fight back or respond in kind to an injury or affront. / (transitive) To repay or requite by an act of the same kind.

To pull (something) back or back inside. / (rare) To avert (one's eyes or a gaze). / (phonetics) To pronounce (a sound, especially a vowel) farther to the back of the vocal tract.