一いっ進しん一いっ退たい

noun, noun or participle which takes 'suru', intransitive verb, noun which may take the genitive case particle 'no'

ebb and flow; seesawing; alternating progress and retreat

Describes a situation that repeatedly improves and worsens, with no clear resolution. Often used for illness, negotiations, or battles.

• 病びょう状じょうは一いっ進しん一いっ退たいを繰くり返かえしている。

  His condition has been fluctuating, repeatedly improving and worsening.