A person who provides a grubstake; an investor who supplies a prospector or entrepreneur with money or supplies in exchange for a share of profits.
From 'grubstake' + '-er' (agent suffix creating a noun for someone who does an action). Common pattern in American English for occupational terms.
The grubstaker was a crucial figure in American expansion—these investors funded the dreamers and explorers, and the word celebrates their role in literally staking claims to the frontier!
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