Trim out misguided experiments, seeing outlay involved (7)
I believe the answer is:
expense
'trim' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for expense that I've seen before include "Money spent in the course of work" , "Outlay or cost" , "Incurred cost" , "What something costs" , "Charge" .)