dear / deer 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. 👇
dear: (adjective) with or in a close or intimate relationship. (adjective) earnest.
deer: (noun) distinguished from Bovidae by the male's having solid deciduous antlers.
dear: d·IH·r
deer: d·IH·r
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)