Intent on picking the odd runner in Asia (7)
I believe the answer is:
earnest
'intent on picking' is the definition.
'earnest' can be an answer for 'intent' (thesaurus). I am not certain of the 'on picking' bit.
'the odd runner in asia' is the wordplay.
'the odd' means one should take alternating letters.
'in' means one lot of letters goes inside another.
'asia' becomes 'East' (East is an example).
The alternate letters of 'runner' are 'rne'.
'rne' placed into 'east' is 'EARNEST'.
Can you help me to learn more?
(Other definitions for earnest that I've seen before include "Serious, intent" , "art collector" , "Resolute" , "Impassioned" , "Serious; pledge" .)