(rare) An insignificant or contemptible dastard

(transitive) To envelop in a protective case. / (intransitive) To withdraw into such a case.

craniodiaphyseal dysplasia: a rare autosomal-recessive bone disorder that causes calcium to build up in the skull, disfiguring the facial features and reducing life expectancy

simple past tense and past participle of have the world by the bag