Crossword Genius

Seemed unhappy with a low-powered machine (5)

Ross

I believe the answer is:

moped

I'm a little stuck... Click here to teach me more about this clue!

'machine' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for moped that I've seen before include "Was miserable; a vehicle" , "Light motor cycle" , "Sulked - form of transport" , "dejected" , "Light motorbike" .)

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app