Hennessey is a traditional Irish surname that originated from the Old Gaelic name "Ó hAonghusa," meaning "descendant of Aonghus." It is a common surname in Ireland and can be traced back to ancient Celtic roots. The name Hennessey is often associated with qualities such as strength, courage, and loyalty. Individuals with the surname Hennessey are known to be independent, hardworking, and proud of their heritage. Hennessey is a name that carries rich cultural significance and a strong sense of identity.