A contradiction between two beliefs or conclusions that are in themselves reasonable; a paradox.
Late 16th century (in the sense ‘a conflict between two laws’): from Latin antinomia, from Greek, from anti ‘against’ + nomos ‘law’.
“The trouble is the entire novel is an antinomy and so fails to be believable.”
Gerundive (noun) (grammar)
A form of a Latin verb, ending in -ndus (declinable) and functioning as an adjective meaning ‘that should or must be done’.
Middle English (in the sense ‘gerund’): from late Latin gerundivus (modus) ‘gerundive (mood)’, from gerundium (see gerund).