The term in-susceptibilities refers to the inability of someone or something to be affected by a particular factor or condition. Synonyms for this term include immunity, resistance, imperviousness, invulnerability, and insensitivity. Immunity implies a defense against disease, while resistance connotes the ability to withstand attack or pressure. Imperviousness suggests impenetrability to external influence, while invulnerability implies complete protection against harm. Insensitivity, meanwhile, indicates a lack of response or awareness. These synonyms can be used interchangeably depending on the context, but all convey the idea of being unaffected or resistant to specific threats or stimuli.