悩める

From 悩む (nayamu, “to be vexed, to be bothered about something; to suffer physical distress”), as a regular shift to the 下二段 (shimo nidan, “lower bigrade”) conjugation pattern.[1][2][3] Compare a similar shift for つく (tsuku, “to stick to something”, intransitive) and つける (tsukeru, “to stick something to something else”, transitive).

First cited to 1563.[1]

• (Tokyo) なやめ​る [nàyáméꜜrù] (Nakadaka – [3])[3]
• IPA^(key): [na̠ja̠me̞ɾɯ̟ᵝ]

悩(なや)める • (nayameru) 

1. [from 1563] (transitive) to vex, to annoy, to cause distress, to make someone suffer

   Synonyms: 悩ます (nayamasu, “to vex”), 苦しめる (kurushimeru, “to make someone suffer”)

2. [from 1921] (intransitive, rare) to be vexed, to be bothered about something, to be distressed about something

Much like root verb 悩む (nayamu), this derivative nayameru has been used with both transitive and intransitive senses. The transitive sense appears to be far more common.

Ultimately from 悩む (nayamu) in the 連用形 (ren'yōkei, “continuative or stem form”) of nayami + stative / resultative copula あり (ari, “to be”), in the 連体形 (rentaikei, “attributive”) conjugation. See further sound-shift details at り#Japanese:_ri-verb-suffix.

• (Tokyo) なやめ​る [nàyáméꜜrù] (Nakadaka – [3])
• IPA^(key): [na̠ja̠me̞ɾɯ̟ᵝ]

悩(なや)める • (nayameru) 

1. the adnominal or attributive form of stative / resultative 悩めり (nayameri, “has been vexed”)