morn / mourn 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. 👇
morn: NA
mourn: (verb) feel sadness. (verb) observe the customs of mourning after the death of a loved one.
morn: m·AO·r·n
mourn: m·AO·r·n
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)