An amalgamate (noun) is someone who is a mate of someone with amalgams (see amalgam).
Needless to say, because amalgams are shapely legs of someone named Amal, the word amalgamate does not get used often. To be an appropriate use of the word, the person who is being referred to must be a spouse of (possibly common law) or just shacking up at least occasionally with someone named Amal. Not only that, but said person named Amal must have what is considered by the speaker to be shapely legs.
What’s more many people would find it politically incorrect to refer to the shapely legs of someone you are mating, and even more so someone who someone else is mating. Thus, on the exceptionally rare occasions when the use of the word amalgamate is lexically appropriate, it is still generally considered to be socially inappropriate.
Maybe we should just scrub amalgamate from the English language altogether.