More understandable about Shakespearean king and queen (7)
I believe the answer is:
clearer
'more understandable' is the definition.
('clear' can be similar in meaning to 'understandable')
'about shakespearean king and queen' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'shakespearean king' becomes 'lear' (I've seen this before).
'and' says to put letters next to each other.
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'c'+'lear'+'er'='CLEARER'
(Other definitions for clearer that I've seen before include "More transparent" , "Less obscured" , "Less overcast" , "More distinct" , "More intelligible, less cloudy" .)