Man, for example, held back by travel sickness (4)
I believe the answer is:
isle
'man for example' is the definition.
(Isle of Man is an example)
'held back by travel sickness' is the wordplay.
'back by' is a reversal indicator.
'held' indicates a hidden word.
'elsi' is hidden within 'travel sickness'.
'elsi' back-to-front is 'ISLE'.
(Other definitions for isle that I've seen before include "one has water all round" , "Man, for one" , "Dogs, perhaps" , "isolated spot" , "Isolated land" .)