It is a term that refers to a type of insanity. 'Post-' means 'after'. 'Febrile' means 'pertaining to a fever'. Therefore 'post-febrile' means 'pertaining to the period after a fever'.
Post can be a verb or a noun. As a verb, post can mean to add a comment to an online forum, send a letter, or place something on a bulletin board. As a noun, post can mean the part of a fence that is...