Fired Tennis Announcer Sues ESPN ... I Never Called Venus Williams a 'Gorilla'

There's a HUGE difference between "gorilla" and "guerrilla" when referring to Venus Williams -- so says ex-ESPN tennis announcer, Doug Adler, who claims he was wrongly fired after people THOUGHT he was being racist.

Adler was calling a match between Venus and Stefanie Voegele at the Australian Open last month when he claims he commented on an exchange by saying, "You see Venus move in and put the guerrilla effect on ... charging."

Adler says Twitter freaked out and misunderstood what he was trying to say -- wrongly interpreting the comment as racist. Instead, Adler says the term is NOT racist, but rather a "frequently used" word in tennis to describe an aggressive style of play. In fact, Adler says Nike ran a tennis campaign back in the '90s called "Guerrilla Tennis."

Adler says ESPN understood what he meant but made him apologize anyway ... only to fire him a short time later.

Adler says he's screwed professionally because of the way his termination played out in the media -- saying, "No one will hire a 'racist.'"

For the record, Adler says he's "anything but a racist."

He's suing for unspecified damages.