"This kanji dictionary is very thick."
I think people after learning this sentence was confused, but the 'atsui' here has different meaning with 'atsui' = hot, since it has different kanji too. Hope it'll help you :) //sorry for bad English
You are right. But normally dictionaries are not hot. And we are usually not interested in temperature of a dictionary.
So Japanese never interpret this あつい as 熱い.
There could be a の between them. Japanese is an incredibly flexible language, but the more normal way to say it is かんじじしょ. You aren't wrong though~
↑ I think this translation should be correct. It can't be a terribly clever dictionary if the person who has that dictionary couldn't even write the word かんじ in kanji (漢字). :P