What is meant by the term to "give an earnest of one's intentions"?


In Simon Schama’s excellent book “Citizens” I came across this phrase on page 246
“give an earnest of one’s intentions”.
“Increasingly wexed by the position Calonne had placed in him, Louis gave the Minister an earnest of his intentions by permitting the responses to his advertisement to be published.”
Is there a word missing after “earnest” or is the word earnest being treated as a noun. The phrasing looks strange. I look forward to your feedback.

I vote for missing word

It is an old fashioned way of saying that he is making some consideration as evidence of ‘his’ intention to carry out a promise.

He gave me $1,000 as an earnest of his intentions = He gave me $1,000 as proof that he was serious.

Earnest is being treated as a noun. It’s essentially being used as a synonym of “guarantee” or “surety” (which is fairly archaic itself)

Yes. It was a pretty comment usage at one point, and you still see it from time to time. Here’s the Ngram for “give an earnest of” Google Ngram Viewer

An example from 1990 “Governments which give an earnest of their intentions to take parks out of politics. . .deserve every encouragement and support”

Thank you all. I had never come across the term before.

We use it today in the form of “earnest money”, the common term in real estate deals for a non-refundable deposit the buyer places with the seller when the offer is accepted.

It’s the formal form of the colloquial “put your money where your mouth is.”

Nitpick: earnest payments in real estate transactions are often refundable, depending on the terms of the purchase agreement. Nearly all purchase agreements provide that the buyer retains the earnest money if financing proves to be unavailable, for example.

For the record, here’s the OED entry:

There are also citations from Wordsworth (“The primrose flower / peeped forth, to give an earnest of the spring”) and Tennyson (“Their love has never past away / the days she never can forget / are earnest that he loves her yet / whate’er the faithless people say”.)