aloud, loudly, out loud
She tried to stay quiet during the movie, but she laughed aloud at the silly joke.
gently, lightly, quietly, softly, silently, under your breath
deeply, heartily, a lot, really, uproariously
She laughed deeply when her dog tried to catch its own tail.
just, merely, simply
When I told him the joke, he simply laughed and didn't take it seriously.
briefly, a little, shortly
easily, freely
The children laughed freely as they played games in the park.
helplessly, uncontrollably
cheerfully, delightedly, excitedly, happily
incredulously, in disbelief
angrily, bitterly, cynically, derisively, grimly, harshly, hollowly, humourlessly, mirthlessly, ruefully, scornfully, sourly, wryly
She laughed bitterly at the job rejection letter, remembering how confident she had felt during the interview.
together
The children played in the park and laughed together as they chased bubbles.