Handle some arrant humbug (5)
I believe the answer is:
thumb
'handle' is the definition.
(thesaurus)
'some arrant humbug' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'THUMB' can be found hidden inside 'arrant humbug'.
(Other definitions for thumb that I've seen before include "Pollex, in humans" , "Hitchhike - ..... a lift" , "Try to get free ride" , "Attempt to obtain a lift" , "Tom, for example" .)