Converse, obverse, reverse are frequently confused when they mean something which is the opposite of another thing.
Converse applies chiefly to statements or to propositions; typically it implies an interchange or transposition of the important terms.
Converse is not to be confused with contradictory (see under OPPOSITE adj); so long as the important terms are transposed, one proposition is the converse of another whether or not it is its opposite.
Obverse and reverse specifically apply to the two faces of a coin or medal, obverse applying to the one containing the head or principal inscription, reverse to the other; in more general use, obverse refers to the more, reverse to the less, apparent or intentionally conspicuous side or face of something.