Intimidate could be "Duping" if you're lying. . .like "If you don't tell me I'll cut your hand off" when actually you'd never follow through and actually do it.
Similar logic to acting. Like if you're not scary, just pretending to be.
But actual intimidation, in terms of RM mechanics, seems to me to be a Morale check.
So Joe Scary the war troll bellows at Peasant militia, do they run off?
Method 1) Straight Maneuver: Decide how scary Joe is to determine difficulty level (I'd compare Joe's PR bonus to the static maneuver table difficulty modifiers, plus any situational modifiers to determine difficulty) make the pesants do a maneuver of that difficulty + SD, if they fail, they flee. (Partial success could affect this)
Method 2) Do it as a contested roll. Decide maneuver difficulty for Joe, have him roll on the MM table at that difficulty + PR, have the pesants make their roll as 1 above, but +/- Joe's final result on the MM table
Method 3) Do it as a RR of Joe's level vs pesant's level + Joe's PR - Peasant SD.
Only problem is that if you do allow acting, duping, seduction, diplomacy or something similar as a modifier, you'll end up with a much higher scary side mod than the resist scary mod, since there's no "Resistance to fear/terror" skill to balance it out. . .I guess you could use perception vs duping or acting, if the person is just pretending, but if they really are scary, I don't see any skill to use for or against it.
It may be one of those incidents where what is a skill in one system, is a stat in the other. Famous quote from a HERO player who switched to RM in my group, after failing to buy any Perception "Perception is a skill?". . . .in RM, intimidating people seems mostly covered by the Presence stat and situational modifiers, not a developed skill.
No reason you can't use Morale out of combat either. . .if you try to use threatening words or behavior at a dinner party, it would seem to fit.