Ambiguous, use [[grabbing own arm]] or [[grabbing another's arm]]. 

h4. See also

* [[arm hug]] (using both arms to surround another's arm)
* [[holding another's arm]] 
* [[holding own arm]]
* [[holding another's wrist]]
* [[locked arms]] (inner elbows touching)
* [[arm held back]] (a type of [[grabbing another's arm]])
arm grab