Klum say greeting outside Islamic festival (5)
I believe the answer is:
heidi
'klum' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'greeting outside islamic festival' is the wordplay.
'greeting' becomes 'hi' (hi is a kind of greeting).
'outside' means one lot of letters goes inside another.
'islamic festival' becomes 'eid' (eg Eid al-Fitr and Eid al-Adha).
'hi' placed around 'eid' is 'HEIDI'.
'say' is the link.
Can you help me to learn more?
(Other definitions for heidi that I've seen before include "German lady's name" , "lady - from Cologne?" , "Girl's name (from German)" , "book" , "Novel Swiss girl" .)