沈香も焚かず屁も放らず
Meanings
1
neither very good nor very bad; mediocre; having few faults but few virtues
Idiomatic expression describing a person or thing that is unremarkable, neither outstandingly good nor offensively bad. The literal meaning is 'neither burning agarwood nor passing wind' — i.e., doing nothing especially fragrant or foul.
He's the type who neither burns incense nor farts, so to speak — he doesn't leave much of an impression.