Avoid the Spanish upstart, extremely disreputable (5)
I believe the answer is:
elude
'avoid' is the definition.
(I know that elude is a more specific form of the action avoid)
'the spanish upstart extremely disreputable' is the wordplay.
'the spanish' becomes 'el' ('the' in Spanish).
'upstart' becomes 'u' (start of the word 'up').
'extremely' means to remove the middle letters (only the extremes of the word are used).
'disreputable' with its middle taken out is 'de'.
'el'+'u'+'de'='ELUDE'
(Other definitions for elude that I've seen before include "Puzzle" , "Evade; baffle" , "Escape from; baffle" , "Avoid (e.g. capture)" , "Escape adroitly" .)