What is the difference between sonorant and obstruent in phonology?

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I study basic phonology. I enjoy studying this field of linguistics. But I sometimes confuse distinctive feature of sonorant and obstruent.

I know the phonetic meaning of obstruent, which represents stop (plosive) and fricative. But is there +obs representation in distinctive feature? I have seen it by myself. I often see -son. Does -son mean obstruent?

I guess sonorant is the opposite of obstruent. Phonetic sonorant involves vowel, liquid, trill and nasal. Does high sonority involve sonorant? Does low sonority involve obstruent? And can sonorant represent -obs?