Part of speech: Verb
derange mentally, throw out of mental balance
Example: make insane; The death of his parents unbalanced him
Part of speech: Verb
throw into great confusion or disorder
Example: Fundamentalists threaten to perturb the social order
Throw out of kilter, Unbalance, Perturb, Derange
The word "derange" comes from Old French desrengier, which comes from French déranger.
rank – A related word in the same word family.
French spelling conventions explain many of English's 'silent letters' and irregular spellings.