Accurate observance in speech (5)
I believe the answer is:
right
'accurate' is the definition.
(similar in meaning)
'observance in speech' is the wordplay.
'observance' becomes 'rite' (I've seen this in another clue).
'in speech' indicates a 'sounds like' (homophone) clue.
'rite' is a homophone of 'RIGHT'.
(Other definitions for right that I've seen before include "Factual" , "Correct; appropriate" , "Spot-on" , "Correct; political wing" , "A person is entitled to it" .)