lacks / lax 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. 👇
lacks: (noun) the state of needing something that is absent or unavailable.
lax: (adjective) lacking in rigor or strictness. (adjective) pronounced with muscles of the tongue and jaw relatively relaxed (e.g., the vowel sound in `bet'). (adjective) lacking in strength or firmness or resilience. (adjective) emptying easily or excessively.
lacks: l·AE·k·s
lax: l·AE·k·s
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)