Understood tact around Italian (5)
I believe the answer is:
tacit
'understood' is the definition.
(I've seen this before)
'tact around italian' is the wordplay.
'around' means one lot of letters goes inside another.
'italian' becomes 'I' (abbreviation for Italian).
'tact' going around 'i' is 'TACIT'.
(Other definitions for tacit that I've seen before include "Implicitly understood" , "Unvoiced" , "Understood without being put into words" , "Aircraft engine casing" , "Implied without being stated" .)