1. self-contained

constituting a complete and independent unit in and of itself

Example Sentences:
'the university is like a self-contained city with shops and all amenities'

2. collected, equanimous, poised, self-collected, self-contained, self-possessed

in full control of your faculties

Example Sentences:
'the witness remained collected throughout the cross-examination'
'perfectly poised and sure of himself'
'more self-contained and more dependable than many of the early frontiersmen'
'strong and self-possessed in the face of trouble'

Synonyms

• collected
• equanimous
• poised
• self-collected
• self-possessed