Foundation of club as I specified (5)
I believe the answer is:
basis
'foundation' is the definition.
('basis' can be a synonym of 'foundation')
'of club as i specified' is the wordplay.
'of' says the answer is hidden in the clue.
'BASIS' is hidden within 'club as i specified'.
(Other definitions for basis that I've seen before include "Underlying support for a theory" , "Form of support" , "Groundwork, foundation" , "First principle" , "Underlying support (for an idea)" .)