Flee from snakes initially invading European headland (6)
I believe the answer is:
escape
'flee from' is the definition.
(I've seen this in another clue)
'snakes initially invading european headland' is the wordplay.
'initially' indicates taking the first letters.
'invading' means one lot of letters goes inside another.
'european' becomes 'E' (abbreviation e.g. EU).
'headland' becomes 'cape' (I've seen this before).
The initial letter of 'snakes' is 's'.
'e'+'cape'='ecape'
's' placed inside 'ecape' is 'ESCAPE'.
(Other definitions for escape that I've seen before include "Abscond, flee" , "Way out (from difficult situation)" , "Get away from depravity" , "Decamp" , "performance by Houdini?" .)