Information on one European magic spirit (5)
I believe the answer is:
genie
'magic spirit' is the definition.
(I've seen this before)
'information on one european' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'one' becomes 'i' (Roman numeral).
'european' becomes 'E' (abbreviation e.g. EU).
'gen'+'i'+'e'='GENIE'
(Other definitions for genie that I've seen before include "Helpful (?) spirit" , "Magician residing in a lamp" , "Arabian goblin with magic powers" , "Magical being who carries out a person's wishes" , "He came from Aladdin's lamp" .)