FBI Director Kash Patel ain't letting anyone stomp on his name without a fight ... hitting back at Rhode Island Senator Sheldon Whitehouse's criticism by claiming he bars people who "look like" him from his private beach club.

The drama played out on X, where Whitehouse brought up the latest lawsuit in which Patel is named. Whitehouse reposted a Politico report on the suit, and wrote ... "Re: Patel, fourth lawsuit (he’ll have to testify); lies to Congress; jets and partying at our expense -- his day will come."

ICYMI ... Patel is being sued by 3 ex-FBI officers for alleging he and the Justice Department engaged in an illegal "retribution campaign" against them after they helped investigate President Donald Trump’s efforts to overturn the 2020 election.

But, Patel fired back by replying to Whitehouse with a list of -- what he deems -- FBI wins in Rhode Island last year.

Alongside the stats, he wrote ... "How’s that private beach club of yours that doesn’t let people who look like me in? I’ll be the guy knocking on the front door, let’s see if you open… meanwhile this FBI crushing violent crime in Rhode Island for people of every color."

Whitehouse hasn't responded yet -- not publicly, at least. TMZ has reached out to his camp for comment ... but, no word back.

Whitehouse, a Democrat, has served in the Senate representing Rhode Island since he was elected in 2006.