As a Verb or Adjective:
1. In linguistics, the lack of a clear relationship between the form of a word or sign and its meaning.
English = arbitrary
Note:
1. The signer in the video is giving a definition in Auslan for the English term ARBITRARY as it is used in an academic or educational context, especially when talking or writing about linguistics.
2. This is not published because there is no Auslan video explaining it.