Bedouin's domain, not one to be tampered with (5)
I believe the answer is:
nomad
'bedouin's' is the definition.
(I've seen this in another clue)
'domain not one to be tampered with' is the wordplay.
'not' indicates named letters should be taken away.
'one' becomes 'i' (Roman numeral).
'to be tampered with' indicates anagramming the letters.
'domain' with 'i' removed is 'doman'.
'doman' anagrammed gives 'NOMAD'.
(Other definitions for nomad that I've seen before include "One travels from place to place with no permanent home" , "Unsettled character" , "drifter" , "Person wandering" , "A member of a wandering tribe" .)