Mark I want to make (5)
I believe the answer is:
twain
'mark' is the definition.
(Mark Twain)
'i want to make' is the wordplay.
'to make' is an anagram indicator.
'i'+'want'='iwant'
'iwant' with letters rearranged gives 'TWAIN'.
(Other definitions for twain that I've seen before include "A pen-name" , "I want (anag) - US novelist and humorist" , "Mark . . . . . was the pen name of Samuel Langhorne Clemens" , "Mark ..... created Huckleberry Finn" , "Two (arch.)" .)