Physicist badly hurt internally very cross (10)
I believe the answer is:
rutherford
'physicist' is the definition.
(Ernest Rutherford 1871-1937 nuclear physicist)
'badly hurt internally very cross' is the wordplay.
'badly' indicates an anagram.
'internally' indicates the central letters.
'cross' becomes 'ford' (fording is a kind of crossing**).
The middle letters of 'very' are 'er'.
'hurt' is an anagram of 'ruth'.
'ruth'+'er'+'ford'='RUTHERFORD'
(Other definitions for rutherford that I've seen before include "Den" , "Scientist" , "Actress" .)