grocer / grosser are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
grocer: (noun) a retail merchant who sells foodstuffs (and some household supplies).
grosser: (adjective) before any deductions. (adjective) lacking fine distinctions or detail. (adjective) repellently fat.
grocer: g·r·OW·s·er
grosser: g·r·OW·s·er
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)