Annoying verse by former partner, in German originally (6)
I believe the answer is:
vexing
'annoying' is the definition.
(I know that annoying can be written as vexing)
'verse by former partner in german originally' is the wordplay.
'verse' becomes 'v'.
'by' says to put letters next to each other.
'former partner' becomes 'ex' (an ex-partner).
'originally' indicates taking the first letters.
The first letter of 'german' is 'g'.
'v'+'ex'+'in'+'g'='VEXING'
(Other definitions for vexing that I've seen before include "Annoying, worrying" , "Causing irritation" , "Extremely annoying" , "Irking" .)