Interesting how trying to answer others' questions helps you understand things about your own language that you had never thought about before. Generally speaking, no. In Bangla, adjectives are not used in place of nouns. To use your examples, the natural way to say there's evil in that place would be to refer to অশুভ শক্তি (evil power). In the second example, mention of white clothing should be made, as you've correctly identified. I'm trying hard to think of exceptions to this, but they are really few and far between. And generally, in the context of ornate literary or poetic expressions. For example, there are songs that go: আকাশের নীল থেকে... (from the blue of the sky...) and আকাশের হাতে আছে একরাশ নীল... (the sky holds a bunch of blue in its hand...). Also, you may hear of Bangladesh referred to as লাল-সবুজের দেশ (the country of red and green), referring to the colours in our flag. The word খুশি (happiness/happy) can be used as both a noun and an adjective.

Usually no. Some words act both as noun and adjective. e.g. sada (white). o sada pore na. (he doesn't wear white (clothes)) o sada kapor pore na. (he doesn't wear while clothes) For other words you have to add suffix or change it to make it a noun from adjective. asuvo (evil) > asuvota (evilness) neel (blue) > neelima (bluishness) sada/suvro (white) > suvrota (whiteness) sekhane asuvota ache. (there is evil there) If you're wondering adding -ta is the most common way to convert from adjective to noun. But there are exceptions.