Ubiquitous (adjective)	Present, appearing, or found everywhere.<br>Example: Smartphones have become ubiquitous in modern society.<br>Mnemonic: From Latin 'ubique' meaning 'everywhere' — ubiquitous things are, quite literally, everywhere you look.
Ephemeral (adjective)	Lasting for a very short time.<br>Example: The cherry blossoms' beauty is ephemeral, fading within a week.<br>Mnemonic: Think of a mayfly — some species live for only a single day, the definition of ephemeral.
Laconic (adjective)	Using very few words; terse.<br>Example: Asked how the exam went, he gave a laconic 'Fine.'<br>Mnemonic: Named after Laconia, the region around Sparta — Spartans were famous for saying as little as possible.
Obsequious (adjective)	Excessively eager to please or obey; servile.<br>Example: The obsequious assistant agreed with every word his boss said.<br>Mnemonic: Contains the Latin root 'sequi' (to follow) — an obsequious person follows and flatters others to a fault.
Austere (adjective)	Severely simple or plain; stern in manner.<br>Example: The monastery's austere rooms held only a bed and a chair.<br>Mnemonic: Picture a stark, empty room — austere spaces have nothing extra in them.
Cogent (adjective)	Clear, logical, and convincing.<br>Example: She presented a cogent argument that changed the jury's mind.<br>Mnemonic: Shares a root with 'cognition' (thinking) — a cogent argument makes you think 'yes, that's correct.'
Deleterious (adjective)	Causing harm or damage.<br>Example: Smoking has a deleterious effect on lung health.<br>Mnemonic: Sounds like 'delete' — something deleterious deletes your health or wellbeing.
Empirical (adjective)	Based on observation or experiment rather than theory.<br>Example: The study provided empirical evidence that the drug worked.<br>Mnemonic: Think 'experience' — empirical knowledge comes from experience and experiments, not just ideas.