Throwing in the towel and White flag

White flag and throwing in the towel are semantically related In some cases you can use "White flag" instead a noun phrase "Throwing in the towel".

White flag noun - Flag consisting of a piece of white cloth that is hoisted to signal surrender or to ask for a truce.

Throwing in the towel and white flag are semantically related in unconditional surrender topic. You can use "Throwing in the towel" instead a noun phrase "White flag".