Excursionist (7)
I believe the answer is:
tripper
'excursionist' is the definition.
(I know that excursionist can be written as tripper)
This is the entire clue.
(Other definitions for tripper that I've seen before include "Person on pleasure day out - sounds unstable" , "One who makes an excursion" , "person having highly enjoyable experience?" , "who might get a booking?" , "Holidaymaker" .)