IPA: /ɪnˈvaɪrəl/
KK: /ɪnˈvaɪrəl/
Lacking qualities traditionally associated with masculinity; weak or unmanly.
He felt that his actions were seen as invirile by his peers.
Invirile is formed from "in-" (meaning not) and "virilis" (from Latin, meaning manly or masculine). The word describes a state of being not manly or lacking masculine qualities.
Think of 'not' ('in-') being combined with 'manly' ('virilis') to remember that 'invirile' means lacking masculine qualities.