Maximum gettable for beginners on an exam (8)
I believe the answer is:
greatest
'maximum' is the definition.
(similar in meaning)
'gettable for beginners on an exam' is the wordplay.
'gettable for beginners' becomes 'gre' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'an' becomes 'a'.
'exam' becomes 'test' (synonyms).
'gre'+'a'+'test'='GREATEST'
Can you help me to learn more?
(Other definitions for greatest that I've seen before include "Largest or most distinguished" , "''But the . . . . . . . . of these is love'' - Bible" , "Highest in quality or in quantity" , "Best-ever" , "Most important!" .)