this is a little difficult to explain, but i'll try
However: the similar to "but," it implies contrast between two things. Unlike "but" it is usually used at the beginning of the sentence.
ex: I wanted to go to the mall. However, it was closed.
"although" and "even though", as well as "despite" are all very similar. They all mean "in spite of something."
Although it was cold outside, we still went on a walk.
Even though it was cold outside, we went on a walk.
Despite it being cold outside, we went on a walk.
although the chicken was overcooked, I still ate it.
even though the dog looked mean, I still tried to pet it.
Despite my sore throat, I still went to school.
Does this make sense? These types of words are hard to define. You just need to get used to them.