at least

if nothing else (`leastwise'' is informal and `leastways'' is colloquial)

• “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”

not less than

• “at least two hours studying the manual”
• “a tumor at least as big as an orange”