Step on ruler's foot? (8,7)
I believe the answer is:
imperial measure
'step on ruler's foot?' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'step on ruler's foot?' is the wordplay.
'step' becomes 'measure' (synonyms).
'on' says to put letters next to each other.
'ruler's foot?' becomes 'imperial' (I can't explain this - if you can you should believe this answer much more).
'measure' after 'imperial' is 'IMPERIAL MEASURE'.
Can you help me to learn more?
(Other definitions for imperial measure that I've seen before include "yard, for one" , "fluid ounces, for example" .)