It hurts, being long subordinate to judge in Bow (7)
I believe the answer is:
earache
'it hurts' is the definition.
(earache hurts one's ears)
'long subordinate to judge in bow' is the wordplay.
'long' becomes 'ache' (synonyms).
'subordinate to' says to put letters next to each other (in a down clue, some letters go beneath others).
'judge in bow' becomes 'ear' ('hear' - as in to hear a court case - said with the 'H' dropped - a cockney accent.).
'ache' put after 'ear' is 'EARACHE'.
'being' acts as a link.
(Other definitions for earache that I've seen before include "Pain for listener" , "Aural complaint" , "listener's discomfort" , "Pain in aural organ" , "Otalgia" .)