English to Latin Translation please

I could not find "thinker" in any latin dictionary.
The closest I got was Cassell's, which said:
thinker, in gen., render by verb

So you might say something like
is qui libere cogitat
he who thinks freely

or we could take some liberties and say:
cogitator liber
cogitator -- derived from cogito
liber -- free
but a strict Latinist would disapprove.