We're not dropping all name rules for last names, just the word combinations once. Your last name still cannot be a title.
Acceptable: Goldfeather, Leafeye, Doomthunder, Bloodscream, Warfang, Winterhand.
Unacceptable: Thief, Sungod, Annihilator, Necromancer, Madman, Immortal.
If it's an actual job/trade description rather than something more "poetic" sounding, let's say, better to avoid it - even if that was commonplace in the medieval era on Earth.