leased / least 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. 👇
leased: (verb) grant use or occupation of under a term of contract. (verb) engage for service under a term of contract.
least: (noun) something that is of no importance. (adjective) the superlative of `little' that can be used with mass nouns and is usually preceded by `the'; a quantifier meaning smallest in amount or extent or degree. (adverb) used to form the superlative.
leased: l·IY·s·t
least: l·IY·s·t
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)