Sharief al-Homsi shivered, clutched his arms and pretended to go through Syrian regime withdrawal.

Standing before an audience in Damascus, he was telling a joke that would have been unthinkable until just a few weeks before, when President Bashar al-Assad was suddenly ousted after more than five decades of his family’s oppressive rule.

“We need rehab centers. You can’t just take this guy away from our life like that — it has to be gradual,” the 33-year-old comedian and screenwriter said, describing the omnipresent posters and magazine spreads depicting the al-Assad dynasty, to laughter from the crowd. He continued to shake. “They’ll ask us what drug were you addicted to; we’ll say, ‘Bashar al-Assad.’”

It was a night of stand-up in late December at the Zawaya Art Gallery in the heart of the Syrian capital. Half of the comedians performing that night have been living abroad after fleeing the country during the 13-year civil war that ended with Mr. al-Assad’s ouster.

Their routines included standard comedy fare — religion, sex and the pressure to get married — but the biggest punchline of the night was Mr. al-Assad. One comedian referred to him throughout his routine as “that whore.”

The comedians were relishing the chance to say things that for decades Syrians would be too scared to utter even in private company. Fear of the notorious mukhabarat, the secret intelligence service, was ingrained so deeply that Syrians lived with the cautionary warning that “the walls have ears.”

But even as they embraced the liberty to make new jokes, the comedians, like many everyday Syrians, were worried that this new freedom of expression could be fleeting. Ahmed al-Shara, the country’s interim president who leads Hayat Tahrir al-Sham, the Islamist rebel group that ousted Mr. Assad, has promised unity that reflects Syria’s diverse population, but there are deep concerns about how democratic and inclusive the government will be.