let alone

let alone  {conj. phr.}
1. Even less; certainly not. — Used after a negative clause.
I can't add two and two, let alone do fractions.
Jim can't drive a car, let alone a truck.
2. let alone or leave alone  {v.}
To stay away from; keep hands off; avoid.
When Joel gets mad, just let him alone.
Little Patsy was warned to leave the birthday cake alone.
Compare: LET BE.
Categories: conjunction verb

'let alone' on video