Crossword Genius

Old pet’s ears given a spraying to get ticks off (11)

Ross

I believe the answer is:

exasperates

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

'ticks off' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how one could define the other.

'old pet's ears given a spraying' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'given' is a charade indicator (letters next to each other).
'spraying' indicates an anagram.
'pets' put after 'ears' is 'earspets'.
'earspets'+'a'='earspetsa'
'earspetsa' anagrammed gives 'asperates'.
'ex'+'asperates'='EXASPERATES'

'to get' is the link.

Can you help me to learn more?

I've seen this clue in The Guardian.
Want a hint initially instead of a full solution? Install my app