English has a lot of different words with similar but slightly differing meanings.
Does "deffering" here means "distinctive"
Differing just means, well, to differ. To be different. "Distinctive" means quite different, easily distinguished.
If I had written this sentence, I'd leave out the first "different" and replace the word "differing" with it: "English has a lot of words that have similar but slightly different meanings." Or, "English has a lot of words whose meanings differ only slightly."