Digit to learn about with hesitation (7)
I believe the answer is:
numeral
'digit' is the definition.
(I know that digit can be written as numeral)
'learn about with hesitation' is the wordplay.
'about' is an anagram indicator.
'with' means one lot of letters goes inside another.
'hesitation' becomes 'um' (um is said in hesitation).
'learn' is an anagram of 'neral'.
'neral' enclosing 'um' is 'NUMERAL'.
'to' acts as a link.
(Other definitions for numeral that I've seen before include "Symbol representing one or two, perhaps?" , "Symbol for number" , "Eg, 5, nine or 6301" , "Eg, two or seven" , "Counting symbol" .)