Crossword Genius

Shy pharmacist upset about patient's first greeting (5,9)

Ross

I believe the answer is:

happy christmas

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'greeting' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'shy pharmacist upset about patient's first' is the wordplay.
'upset' is an anagram indicator.
'about' is an insertion indicator.
'patient's first' becomes 'p' (1st letter of 'patient').
'shy'+'pharmacist'='shypharmacist'
'shypharmacist' is an anagram of 'hapychristmas'.
'hapychristmas' placed around 'p' is 'HAPPY CHRISTMAS'.

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I've seen this clue in The Telegraph.
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