Philosopher known for his razor (5)
I believe the answer is:
occam
'philosopher known for his razor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for occam that I've seen before include "___ 's razor - computer programming language" , "Oxford scholar" , "Man with razor" , "English philosopher, William (with a Razor!), d. 1349" , "medieval philosopher" .)