Obsess v. t. : To besiege; to beset.

Example:
Why do professional athletes Obsess over maintaining an extremely low body fat?

Taxonomy
obsess, Merriam-Webster Online Dictionary, Dictionary, webster, obsessed, Word Games, Webster Online Dictionary with audio pronunciations, thesaurus, glossary, english, language, ESL, Search, sess, äb, Etymology, Latin, past participle.

Defination from the web:
obsess from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... Learn more about "obsess" and related topics at Britannica.com. Pronunciation Symbols. Share this entry: Link to this page: Cite this page: Products ...