"It was a joke, off-colour or whatever," Renner said on US talk show Conan.
"We were talking about a fictional character and fictional behaviour.
"But if you slept with four of the six Avengers, no matter how much fun you had, you'd be a slut. I'm just saying."
The controversy began in April when Renner and co-star Chris Evans joked about Black Widow's love life in an interview with Digital Spy.
Unsurprisingly Renner's latest comments have not gone down well with fans.
"Dear Jeremy Renner, Black Widow is a fictional character and she cannot hear you. Every woman in the world is a real person and THEY CAN," Sunil Patel wrote on Twitter.
"The more Jeremy Renner talks about the Black Widow, the less of a likable human being he becomes," Sam tweeted.
But there were some who came to his defence.
"The people who are upset wtih Jeremy Renner's comments about Black Widow have no reason to get offended. It did no harm and had no intention to," Hayley tweeted.
- AAP