Disclaimer: Not a native speaker.
The difference between טעים and טעימה is that one is masculine and one is feminine. In my experience, this is not a formal/informal distinction in any language, and if you use the wrong gender, it sounds weird. The only exceptions I can think of are words which for whatever reason are often mistakenly assigned the wrong gender by native speakers, in which case a non-native will be less likely to raise eyebrows making the same mistake.
But (again, IME), using the wrong gendered adjective in a language where adjectives agree with nouns is as weird as calling a man "she" or a woman "he" in English.