Second dismissal having unfortunate consequences (10)

I believe the answer is:

backfiring

I'm a little stuck... Click here to teach me more about this clue!

'having unfortunate consequences' is the definition.
I can't judge whether this definition defines the answer.

'second dismissal' is the wordplay.
'second' becomes 'back' (to second a motion is to back it).
'dismissal' becomes 'firing' (synonyms).
'back'+'firing'='BACKFIRING'

Can you help me to learn more?

(Other definitions for backfiring that I've seen before include "proving a disastrous failure" , "producing an own goal" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app