this is postgresql question..how do i drop unique constraint on a column?

content in content table has unique constraint..(although i can't see it
with \d content)

how can i drop that constraint?
thank you

mydb=# \d content
Table "content"
Attribute | Type | Modifier
-----------------+---------+----------
content_id | integer | not null
content | text | not null
title | text |
description | text |
content_type_id | integer | not null
Indices: content_content_key,
content_pkey

mydb=#