[rosignol]

Here's what I go by for combat skills.

10: green (parry 8, knows which end hurts)
12: rookie (parry 9, usually doesn't hurt himself)
14: squaddie (parry 10, can hit other guy reliably)
16: competent (parry 11, can hit hands and vitals reliably)
18: dangerous (parry 12, can use deceptive attack reliably)
20: vicious (parry 13, can use rapid strike reliably)
22: deadly (parry 14, can hit eyes reliably)
24: master (parry 15, fighting this person is a death sentence)

Of course, as the consequences of using most non-combat skills are generally not nearly as bad as what can happen when using combat skills, I'd expect the comparable levels to be 2-4 points lower.