The word 'evangelical' has been hijacked to mean anti-gay, anti-science and anti-immigrant, Rob Bell has said, condemning the way it's used in the US to refer to a "very narrow voting block".

"Whenever there's an election, there's all this talk about who the 'evangelical voters' are going to go with, and the 'evangelical voting block' – who are they going to side with?" the former megachurch pastor said in a YouTube video posted last Thursday.

"And when I hear that every time I just want to throw up. How did this word 'evangelical' come to mean what it means in our world?"

Bell went on to explain the root of the word evangelical. He said it was originally used by the Roman Empire when it proclaimed the 'good news' of having conquered other armies and lands.

"Now, a couple of thousand years ago...with the Roman Empire crushing everybody in its path, a small movement started among a group of people who believed that their leader, Jesus, had risen from the dead. And they believed that this was good news; that death doesn't have the last word...And so they took this Roman propaganda that said Caesar was Lord, and they said among themselves, 'Jesus is Lord'," he said.

The early church took the idea of good news "and said 'it's not good news when you destroy your enemy; it's good news when you love your enemy, and when you side with the widow, the poor, the immigrant and the stranger among you,'" Bell added.

"So the idea that a couple of thousand of years later, the word 'evangelical' refers to a very narrow voting block, with a couple of very narrow policies – it's so far from how it started, it's not even comprehensible."

Bell insisted that Christians need to "take back" the word. "Evangelical means good news, and it's good news for everybody that doesn't fit in...How did the word evangelical get hijacked like this?" he asked.

"We should take back this word as the joyous, buoyant announcement of good news that death, oppression and violence don't have the last word.

"If it isn't good news for everybody, then it isn't good news for anybody. And for many people the word evangelical has come to mean anti-gay, anti-science, anti-immigrant and it's so far from it's original intent which was the good news of God's love extended to everybody who's ever felt the boot of the empire on their neck.

"The word's been hijacked and it's wrong and we need to take it back. I'm an evangelical, and I believe in good news for everybody," he finished.

Previously embraced by evangelicals for his ability to draw people to the Bible and Jesus in creative ways, Bell caused controversy in 2011 when he published Love Wins, a book questioning the existence of hell. Though he had long encouraged Christians to think critically about faith, many people saw this as a step too far and he was widely accused of heresy. John Piper famously tweeted "Farewell, Rob Bell".

Bell, however, appeared to remain unphased. "I never spent a minute wondering whether I'm in or out," he told Religion News Service of his position as an evangelical.

"If we mean Jesus' message of God's revolutionary love for every person, and we can surrender and give our life to acts to loving kindness, then man, sign me up."