Throw out online winner having no alternative (5)
I believe the answer is:
evict
'throw out' is the definition.
(evicting is a kind of throwing out)
'online winner having no alternative' is the wordplay.
'online' becomes 'e' (as in e-mail or e-commerce).
'winner' becomes 'victor' ('victor' can be a synonym of 'winner').
'having no' indicates named letters should be taken away.
'alternative' becomes 'or'.
'victor' with 'or' taken out is 'vict'.
'e'+'vict'='EVICT'
(Other definitions for evict that I've seen before include "Expel from a dwelling" , "remove from home" , "Throw out, expel" , "Oust" , "Put out of house as for non-payment" .)