Revolutionary nearly put frighteners on Mrs Siddons? (5)
I believe the answer is:
sarah
'mrs siddons?' is the definition.
(actress Sarah Siddons is an example)
'revolutionary nearly put frighteners on' is the wordplay.
'revolutionary' is a reversal indicator.
'nearly' means to remove the last letter.
'put frighteners on' becomes 'harass' (both can mean to intimidate or terrorise).
'harass' with its final letter removed is 'haras'.
'haras' back-to-front is 'SARAH'.
(Other definitions for sarah that I've seen before include "Lady" , "Girl" , "Woman" , "- Bernhardt, Fr. actress" , "Girl's name" .)