flecks / flex 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. 👇
flecks: NA
flex: (noun) the act of flexing. (verb) contract. (verb) exhibit the strength of. (verb) bend a joint. (verb) cause (a plastic object) to assume a crooked or angular form.
flecks: f·l·EH·k·s
flex: f·l·EH·k·s
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)