Is this ruleset to be themed around musclebound swords-and-sorcery, or more generic?
In the former case, the language of “Howardese” seems a good ideal. This is the language in which daggers can be dripping “redly” with blood.
I think that in passages relating to physical prowess, REH was rather enamoured with words like “thews” and “sinew”.
Going beyond language alone, situations relating to keenness of mind were generally to do with shrewdness, cunning and craft as opposed to things like sagacity, knowledge or enlightenment.
But again, this is all assuming it’s not to be a generic or wide-scope fantasy ruleset.