Proficient in tables (4)
I believe the answer is:
able
'proficient' is the definition.
(able can mean capable or proficient)
'in tables' is the wordplay.
'in' says the answer is hidden in the clue.
'ABLE' can be found hidden inside 'tables'.
(Other definitions for able that I've seen before include "Having the skills and qualifications required" , "Practised" , "Having great proficiency or intelligence" , "Competent, having ability" , "Competent as seaman may be" .)