Single parliamentarian got extremely eccentric telegram? Perfect (10)
I believe the answer is:
impeccable
'perfect' is the definition.
(similar in meaning)
'single parliamentarian got extremely eccentric telegram?' is the wordplay.
'single' becomes 'I' (one).
'parliamentarian' becomes 'MP' (Member of Parliament).
'got' means one lot of letters go next to another.
'extremely' suggests removing the centre (letters on the extremes of the word are used).
'telegram?' becomes 'cable' (cable is a kind of telegram).
'eccentric' with its middle taken out is 'ec'.
'i'+'mp'+'ec'+'cable'='IMPECCABLE'
(Other definitions for impeccable that I've seen before include "In accordance with the highest standards" , "Faultless" , "Immaculate" , "Perfect - pure" , "Without fault" .)