John, this is an informal word to express annoyance at someone or a situation.
When we say someone took his "bloody time", we are annoyed that they have taken a long time to get something done.
Another meaning is something violent and involves the loss of lives, bloodshed or cruelty.
The Civil War was a bloody chapter in the country's history.
Just as a side discussion, "bloody" is used with other nouns such as "idiot" and "fool" to express our anger at someone's inconsiderate or senseless behaviour.
"Bloody" can also he used in other ways: A "Bloody Mary" does not involve any spillage of blood. It is an alcoholic drink.
Hope this helps.
Cheer,
Lance