less than anything or anyone else [≠ most]:
The journey would impose extra expense on those least able to afford it.
It is quite amazing what turns up when you are least expecting it.
He's my least favourite member of staff.
especially not a particular person or thing:
She hardly ever lost her temper - least of all with Anne.
used to emphasize that something is important:
My mother was upset about his appearance here, not least because she felt it was invading her privacy.