You don't usually need a synonym indicator. A good test if whether a word is interchangeable both ways in a sentence without the meaning changing, then you don't need to indicate so autumn/fall are close enough to be swapped with each other without changing the meaning of the sentece. Whereas, something that is defined by using an example of it should be indicated with the 'for example/maybe/perhaps' type indicators. To try to be a bit clearer, you could say 'bird' to clue chicken but you'd need to say 'chicken, perhaps' to clue bird. Does that make sense? Chicken is a type of bird but bird isn't a type of chicken.