Provide defence for politician arrested in capital (5)
I believe the answer is:
alibi
'provide defence' is the definition.
I can't judge whether this definition defines the answer.
'politician arrested in capital' is the wordplay.
'politician' becomes 'lib'.
'arrested in' is an insertion indicator.
'capital' becomes 'AI' (resembles A1, which can mean capital or excellent).
'lib' put into 'ai' is 'ALIBI'.
'for' is the link.
Can you help me to learn more?
(Other definitions for alibi that I've seen before include "Legal excuse" , "Evidence one was not present" , "that gets him off the hook?" , "Cover story" , "Legal defence, plea" .)