This paper seeks to examine Samuel Johnson's notions of poetical language as related to his work as a lexicographer. It argues that Johnson's ideas about, and ideals of, the language appropriate to poetry derive largely from his work on his Dictionary. It attempts to restore the connection between the two spheres of Johnson's activities. It also examines the unusually stringent semantically-based criticism of poetry in Johnson's critical work, especially The Lives of the Poets. As a showcase, the author examines Johnson's negative critical comments on Thomas Gray's poetry. The attention lies on expressions used by Grey that Johnson found particularly objectionable, including the word "buxom" ("Ode on Spring"); these criticisms are examined in detail. The paper compares Wordsworth's opinion of Gray's diction with Johnson's, and finds them surprisingly similar. It concludes that Johnson may have regretted poets' (and other users') deviation from logical etymological derivation of the meanings of words, and believed that the poets wrote bad poetry as a result; yet he also accepted to some extent the inevitable "encroachment" of metaphorical meanings.