dǐ​xiàn HSK7

bottom line

底线 (底線) dǐ​xiàn
bottom line noun
the limit of what one is prepared to accept

His behavior has already crossed my moral bottom line.

baseline noun
the line marking each end of a court in sports such as tennis or basketball

The tennis ball landed near the baseline.

spy noun
an undercover agent, informer, or plant within an organization

Operating with integrity is a bottom line that every merchant must uphold.

under thread noun
the lower thread in a sewing machine

The bobbin thread of the sewing machine broke and needs to be reinstalled.

Frequency

Movie subtitles
10.1 per million appears in 4% of films
Written text
16.7 per million

Details

HSK 3.0
Level 7

Sources

Definitions
CC-CEDICT