Third party and Unbiased observer

Third party noun - Someone other than the principals who are involved in a transaction.

Unbiased observer and third party are semantically related. in group other than principals topic. In some cases you can use "Unbiased observer" instead a noun phrase "Third party".

Third party and unbiased observer are semantically related. Sometimes you can replace phrase "Third party" with "Unbiased observer", this phrases are similar.