As @Darkgamma says, we don't know. The closest we have would probably be ghâsh, which means fire, and one could probably guess that the characteristic of being fire-like would be something like ghâshum, but there is no empirical evidence for that, except that the suffix -um seems to mean -ness, as in burz- (meaning dark) + -um (meaning -ness), put together ...
In short: no.
In a bit long: not really, and some people have gone to the effort of analysing the Black Speech. In essence, the list of words we know thus far is rather scant:
-at infinitive suffix, or possibly a specialized "intentive" suffix indicating purpose: Ash nazg durbatulûk "one Ring to rule them all"
One popular proposal that comes up in a lot of discussions on this topic is to base it on the direction of the official writing system (i.e. Latin characters). Thus "poki open" for left, and "poki pini" for right. However, there is still no real consensus on how to say "right" and "left", so these expressions might not be understood by everyone.
Building on the answer by thrig: one could say poka pilin (side with a heart) for the left side and poka pilin ala for the right side.
It should be rather neutral and understandable as it is based on biology facts instead of culture-specific ideas.
The consensus answer (thanks Oliver Mason) for how to translate Haters gonna hate into Toki Pona is the following:
tenpo ale la jan ike li ike
Tenpo ale la translates as at all times and captures the sense of inevitability in haters gonna hate in English. It also serves to rule out other possible readings such as the tautological bad people are bad. Here ...
I'd say something like
jan pi lawa ike li wile e ijo ike tawa sina lon tenpo ale
Which means: "People of bad heads want bad things for you, always".
You could also use:
jan pi toki ike li wile e ijo ike tawa sina lon tenpo ale
Which means: "People of bad talking want bad things for you, always".