Bailiff seizes pair, one let off (8)
I believe the answer is:
reprieve
'let off' is the definition.
(I've seen this before)
'bailiff seizes pair one' is the wordplay.
'bailiff' becomes 'reeve' (I've seen this in another clue).
'seizes' means one lot of letters goes inside another.
'pair' becomes 'pr' (abbreviation).
'one' becomes 'i' (Roman numeral).
'pr'+'i'='pri'
'reeve' going around 'pri' is 'REPRIEVE'.
(Other definitions for reprieve that I've seen before include "Let off punishment" , "Delay execution of" , "Grant stay of execution" , "Postponement of trouble or sentence" , "left off the hook" .)