Somewhere in my story I have Leks laughing thunderously. And that's a problem, because Leks is an old man. He's a very fit old man - despite being an amputee - but still, he's old. He's not large either. In fact, he's a rather small guy. Tough, wiry. Retired gangster. He does not laugh thunderously.

I can actually hear inside my mind how he sounds when he laughs, and it's more something of a cackling laugh - but not loud or irritating, which makes me feel I can't use cackling either.

So I need another word, and while the thesaurus is usually a big help, it isn't this time. What would you suggest?

Just a thought.  Maybe consider crackling.  A crackle doesn't have to be particularly loud, but it's always noticeable.

Gyppo

Nice! That sounds about right. Thank you.

Or use a simile.

He laughed like a Democrat watching Donald Trump fail a senility test.

A simile has its merits too, but I'll go with Gyppo's suggestion in this case. It just fits.

But thanks anyway. Your suggestion might well come in handy later. I'll keep it in mind.