Crossword Genius

One who knows everything later changed in taste (5,5)

Ross

I believe the answer is:

smart aleck

'one who knows everything' is the definition.
(term for a know-it-all)

'later changed in taste' is the wordplay.
'changed' indicates an anagram.
'in' is an insertion indicator.
'taste' becomes 'smack' (a smack of something is a taste of it).
'later' anagrammed gives 'rtale'.
'rtale' put into 'smack' is 'SMART-ALECK'.

(Other definitions for smart aleck that I've seen before include "Wise guy" , "Upstart" , "Know-all" .)

I've seen this clue in The Telegraph.
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