A karl, charl, carl, ceorl or cearl
is a man, and a free man (as opposed to a thrall), but it more precisely
means "señor", i.e. "old man" used as a term for a certain class of man, but also more simply where we might say "old man" today, there being no precise equivalent of "señor". The English forms Ceorl and Cearl (depending on the dialect) are recorded as names in the 6th and 9th C., but it's usually the final element of dithematic names and so not normally used alone. The OHG forms are Charl and Charal, but that may be the southern form, the MHG form recorded as Kerl, closer to the
Dutch and Icelandic forms. Note that
Karl does not appear as a name till quite late — aside from the English Cearl/Ceorl, Forstemann only records variations on
Carolus, Carlefred, and variations on
Carloman which may be derived from
Carolus magnus. On the other hand Hariolus is really the wrong form to correspond to
Carolus — the usual form is Heril, Herilo, later Herle or Romance Arle (the latter indistinguishable from Arl from Erl);
Carolus more formally corresponds to Garo-, from Gar- spear(point), which also becomes
Charo- and Caro- in Romance languages.