I'm a non-native English speaker (agravated by the fact that I'm Spanish!), and this is how I explain it to my non-native English speakers students in the sim:
Dynamic maneouver is when, to maintain a constant output (for example V2+10 on take off), you have to keep changing and adjusting the input (pitch attitude) due to the constant changes in the factors that affect that input (less thrust with higher altitude, raising the gear, deflection of the flight controls that create drag, etc...). Leaving the input unchanged doesn't guarantee an unchanged output as well.
This seems to help them understand that concept. Or at the very least, they stop frowning...