1. the quality of being unsuitable or inappropriate for a particular purpose or situation
Usage: formal
2. lack of natural ability or skill
Usage: formal

Examples

• The unaptness of his casual attire for the formal dinner was immediately apparent.
• Her unaptness for leadership became clear during the crisis.
• The committee questioned the unaptness of the proposed solution.
• His unaptness in mathematics made the advanced course particularly challenging.
• The unaptness of the timing could not have been worse.
• She recognized her own unaptness for public speaking.