Understand Shakespearean king and knight (5)
I believe the answer is:
learn
'understand' is the definition.
(thesaurus)
'shakespearean king and knight' is the wordplay.
'shakespearean king' becomes 'lear' (I've seen this before).
'and' says to put letters next to each other.
'knight' becomes 'n' (chess).
'lear'+'n'='LEARN'
(Other definitions for learn that I've seen before include "Comprehend" , "Take in" , "Gain knowledge or skills" , "Acquire knowledge or skill" , "teach illiterate" .)