To release hidden stress or pent-up emotions, often to a friend or
significant other.
Sometimes harmful depending on the way it is released, such as
forcefully or angrily, but it can also be released emotionally. Sometimes just talking about the topic helps people vent and be in a better mood.
"I really need
someone to vent to..."
Sometimes, if you can't sleep, you just need to vent.
"Thomas just
vented to me and I feel really bad for him"