out of shape
Definitions
In poor physical condition due to a lack of regular exercise.
Not in the proper or intended physical form or state.
Examples
I feel completely out of shape after sitting at my desk for the past six months.
He realized he was out of shape when he got winded just walking up a single flight of stairs.
If you want to run a marathon, you need to start training because you are currently quite out of shape.
Synonyms
unfit out of condition flabby soft sedentary out of practice unconditioned