inaptness

A moment's relaxation, or inaptness, may forfeit opportunity, offered only by chance and not to be regained by effort.

She started to leave, furious with herself for her inaptness, and instead of going she paused and turned back.

The secret lies in the inaptness of the South Italians for good team work.

In this hope he was deceived by his own inaptness and his adversary's readiness.

The same inaptness and incompetency for general management characterized the English chiefs as at the very beginning of the siege.