last month; previous month
Refers to the month immediately before the current one, often used in business or formal contexts.
Last month's sales were strong.
It increased by 10% compared to the previous month.
前月 means 'the previous month,' the direct opposite of 翌月, which means 'the following month.'
month-over-month; compared to the previous month
Compound of 前 (previous) and 月 (month).