From ennoyer (“to flood; to inundate”) + -ment. IPA(key): /ɑ̃.nwa.mɑ̃/ ennoiement m (plural ennoiements) flooding, inundation...
a silent 'e'. Conjugation of ennoyer (see also Appendix:French verbs) ennoiement “ennoyer”, in Trésor de la langue française informatisé [Digitized Treasury...