ろく
rokuni

Adverb

1. (not) well; (not) properly; (not) enough; (not) sufficiently; (not) satisfactorily; (not) decently

Usually Written in Kana
昨夜 さくやはろくに ねむれなかった。
sakuyawa rokuni nemurenakatta.
I could not sleep much last night.
Other forms: