Stanhope for one in time becomes mediocre (7)
I believe the answer is:
average
'mediocre' is the definition.
(synonyms)
'stanhope for one in time' is the wordplay.
'stanhope for' becomes 'vera' (I can't justify this - if you can you should give a lot more credence to this answer).
'one in' means one lot of letters goes inside another.
'time' becomes 'age' (an age is a period of time).
'vera' inserted within 'age' is 'AVERAGE'.
'becomes' acts as a link.
Can you help me to learn more?
(Other definitions for average that I've seen before include "Mean - typical" , "mean maybe" , "Normal amount" , "Mean figure?" , "Mean - everyday" .)