simple past tense and past participle of defeat
"The team was defeated in the final match last night."
In plain English: Defeated means to win against someone so they lose and cannot continue fighting.
"The team defeated their opponent in the final match last night."
disappointingly unsuccessful
"disappointed expectations and thwarted ambitions"
"their foiled attempt to capture Calais"
"many frustrated poets end as pipe-smoking teachers"
"his best efforts were thwarted"
Subjugated, beaten, overcome.
"The army was defeated by the enemy's superior tactics and forced to retreat across the river."
In plain English: Defeated means feeling completely beaten up and unable to keep trying after losing something important.
"After losing the final match, he returned home feeling completely defeated."
The word defeated is formed by adding the past tense suffix to defeat. It entered English as a standard grammatical form indicating that an action of overcoming has been completed.