Evangelist is friendly but lacking in enthusiasm (8)

I believe the answer is:

lukewarm

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'lacking in enthusiasm' is the definition.
'lukewarm' can be an answer for 'enthusiasm' (I have seen 'Little enthusiasm' mean 'lukewarm' so perhaps 'enthusiasm' could also mean 'lukewarm'). I'm unsure of the 'lacking in' bit.

'evangelist is friendly' is the wordplay.
'evangelist' becomes 'Luke' (one of the four Christian evangelists).
'is friendly' becomes 'warm' (synonym).
'luke'+'warm'='LUKEWARM'

'but' acts as a link.

Can you help me to learn more?

(Other definitions for lukewarm that I've seen before include "Unenthusiastic" , "Rather cool" , "Little enthusiasm" , "Tepid, or less than enthusiastic" , "Not enthusiastic, neither hot nor cold" .)

I've seen this clue in The Irish Times.

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