1) Impotence 1) Lack of efficiency 2) Unskillfulness 
The term inefficiency has several meanings depending on the context in which its used: Productive inefficiency, Resource-market inefficiency and X-inefficiency might be analyzed using Data Envelopment Analysis and similar methods. ...
• (n.) The quality of being inefficient; want of power or energy sufficient; want of power or energy sufficient for the desired effect; inefficacy; incapacity; as, he was discharged from his position for inefficiency.
In`ef·fi'cien·cy noun The quality of being inefficient; want of power or energy sufficient for the desired effect; inefficacy; incapacity; as, he was discharged from his position for inefficiency . 
[n] - unskillfulness resulting from a lack of efficiency
noun unskillfulness resulting from a lack of efficiency
the quality or condition of being inefficient; lack of efficiency. · an instance of inefficiency: This work is riddled with inefficiencies.