Note pair rashly beginning to date (5)
I believe the answer is:
sofar
'note pair' is the definition.
The definition suggests a singular noun which matches the answer.
'rashly beginning to date' is the wordplay.
'beginning' indicates taking the first letters.
'to' says to put letters next to each other (I've seen this in other clues).
'date' becomes 'sofa' (I can't justify this - if you can you should believe this answer much more).
The first letter of 'rashly' is 'r'.
'r' after 'sofa' is 'SOFAR'.
Can you help me to learn more?
(Other definitions for sofar that I've seen before include "To this point" , "Up till now" , "'Up to this time (2,3)'" , "'Heretofore (2,3)'" , "Up until the present moment" .)