impotent
/ɪmpəʊtənt/Definitions
1. adjective
Lacking the power or ability to do something, or unable to have an erection.
“The impotent king was unable to defend his kingdom against the invading army.”
2. noun
A person who is unable to perform sexually, or is unable to have an erection.
“The doctor told the man that he was suffering from impotence and would need medication to cure it.”