Doddering lines about European (6)
I believe the answer is:
senile
'doddering' is the definition.
(I know that doddering can be written as senile)
'lines about european' is the wordplay.
'about' indicates anagramming the letters.
'european' becomes 'e' (abbreviation e.g. EU).
'lines' with letters rearranged gives 'senil'.
'senil'+'e'='SENILE'
(Other definitions for senile that I've seen before include "Suffering from weaknesses of old age" , "Gaga" , "Suffering from old age's weaknesses" , "Doddering" , "Affected by old age" .)