fǎn​fǎn​fù​fù

fluctuate

反反复复 (反反復復) fǎn​fǎn​fù​fù
fluctuate descriptive
recurring or shifting back and forth; unstable or inconsistent
repeatedly adverb
doing something many times over; time and time again

Frequency

Movie subtitles
0.920 per million appears in 1% of films
Written text
1.64 per million

Sources

Definitions
CC-CEDICT