Become disillusioned let ashore abroad (4,5)
I believe the answer is:
lose heart
'become disillusioned' is the definition.
(I've seen this before)
'let ashore abroad' is the wordplay.
'abroad' indicates an anagram (abroad can mean moving around).
'let'+'ashore'='letashore'
'letashore' is an anagram of 'LOSE HEART'.
(Other definitions for lose heart that I've seen before include "get discouraged?" , "Falter in courage - or fall in love? (4, 5)" , "Start to despair" , "Here's a lot to cause courage to ebb" , "Become despondent" .)