N5
いち
Definition
one, best, first, foremost, beginning, start, bottom string (on a shamisen, etc.)
N4
おいわい
Definition
congratulation, congratulations, celebration, festival, congratulatory gift
N3
いがい
Definition
unexpected, surprising
N2
いいつける
Definition
to tell (to do), to order, to charge, to direct, to tell on (someone), to report, to often say
N1
あっけない
Definition
not enough, too quick (short, long, etc.)