dammed / damned 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. 👇
dammed: (verb) obstruct with, or as if with, a dam.
damned: (noun) people who are condemned to eternal punishment. (adverb) in a damnable manner.
dammed: d·AE·m·d
damned: d·AE·m·d
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)