Definitions
Century Dictionary and Cyclopedia
- Composed; not disturbed.
Wiktionary
- adj. in full control of one's faculties, and having a firm belief in one's abilities; confident, assured and poised
GNU Webster's 1913
- adj. Composed or tranquil in mind, manner, etc.; undisturbed.
WordNet 3.0
- adj. in full control of your faculties
Examples
“The very young, self-possessed, blond girl in the bright red sleeveless dress in "Glass Door" 2006 sits on the floor with her back to a window.”
“So throughout my journey, I definitely identified much more closely with the struggling hero archetype than with the self-possessed goddess archetype.”
“After grabbing glasses of water, I began asking her questions ranging from how she balances work and family to how she became such a self-possessed businesswoman.”
“He states that the art world "has been hijacked by the very same forces that poisoned the world of finance: herding, greed and short-termism leading to asset inflation, market collusion, lack of substance and too many self-possessed individuals.”
The Huffington Post: Brian D. Cohen: The One-Percenter Art World
“So what on earth was such a woman, a masterful, strident, self-possessed and sharp-edged woman, doing to herself with a man who repeatedly betrayed and humiliated her?”
“The Hollywood Reporter's Todd McCarthy calls Gosling's performance a "bid to enter the iconic ranks of tough, self-possessed American screen actors -- Steve McQueen, Clint Eastwood, Lee Marvin.”
The Huffington Post: Ryan Gosling turns tough guy for thriller "Drive"
“But the exercise relieved some of the tension he was feeling and helped him compose the calm, self-possessed image he wanted to portray on camera.”
“The difference between them lay in that she was cool and self-possessed while his face flushed to the roots of the hair.”
“Immediately Tudor's monkey-like impishness left him, and he was once more the cool, self-possessed man of the world.”
“She's gorgeous, self-possessed, a terrific actress.”
Casting Populazzi: Who Should Play the Book's Characters on the Small Screen
Lists
‘self-possessed’ hasn't been added to any lists yet.

anydelirium 'I keep my countenance,
I remain self-possessed
Except when a street piano, mechanical and tired
Reiterated some worn-out common song
With the smell of hyacinths across the garden
Recalling things that other people have desired
Are these ideas right or wrong?'
-A Portrait of a Lady, by T.S. Eliot Feb 21, 2008