Meaning : If nothing else (`leastwise' is informal and `leastways' is colloquial).
Example :
At least he survived.
They felt--at any rate Jim felt--relieved though still wary.
The influence of economists--or at any rate of economics--is far-reaching.
Synonyms : at any rate, leastways, leastwise
Meaning : Not less than.
Example :
At least two hours studying the manual.
A tumor at least as big as an orange.
Synonyms : at the least