Noble bashes wagtail, unfortunately (5)
I believe the answer is:
galas
'noble bashes' is the definition.
'galas' can be an answer for 'bashes' (I've seen this before). I'm not certain of the 'noble' bit.
'wagtail unfortunately' is the wordplay.
'wagtail' becomes 'g' (I can't justify this - if you can you should give a lot more credence to this answer).
'unfortunately' becomes 'alas' ('alas' is used to express regret).
'g'+'alas'='GALAS'
Can you help me to learn more?
(Another definition for galas that I've seen is " Bashes".)