Many capsize entering Scottish island base (8)
I believe the answer is:
multiple
'many' is the definition.
(similar in meaning)
'capsize entering scottish island base' is the wordplay.
'capsize' becomes 'tip' (I've seen this in another clue).
'entering' indicates putting letters inside.
'scottish island' becomes 'mull' (Isle of Mull).
'base' becomes 'e' (Euler's number - base of natural logarithms).
'tip' placed inside 'mull' is 'multipl'.
'multipl'+'e'='MULTIPLE'
(Other definitions for multiple that I've seen before include "Having or involving many parts" , "Manifold; numerous" , "Having several parts" , "Several or many" , "Having many parts or components" .)