auxiliary N1 uncommon written

〜損なう — to fail to ~

〜損なうそこなう

Meaning

① fail to do / miss doing (やり損そこなう): fail to ~ / miss the chance to ~ — the action doesn't get done as planned

② do wrongly / botch (書かき損そこなう): ~ wrongly / make a mistake in ~ing — the action is done but botched

① fail to do / miss doing (やり損そこなう)

電車でんしゃに乗のり損そこなって、約束やくそくに遅おくれた。

I failed to catch the train and was late for my appointment.

② do wrongly / botch (書かき損そこなう)

宛名あてなを書かき損そこなって、葉書はがきを一枚いちまい無駄むだにした。

I wrote the address wrong and wasted a postcard.

Attaches to	Form	Example
Verb masu-stem + 損そこなう (conjugates as a godan verb)	V-stem + 損そこなう	やり損そこなう / 言いい損そこなう

〜損そこねる — Common interchangeable variant (乗のり損そこねる, 書かき損そこねる).

① fail to do / miss doing (やり損そこなう)

うっかりして、大事だいじな場面ばめんを見み損そこなった。

I wasn't paying attention and missed the crucial scene.

② do wrongly / botch (書かき損そこなう)

計算けいさんをし損そこなって、合計ごうけいが合あわなかった。

I botched the calculation and the total didn't add up.

After certain verbs it means 'come close to (a bad outcome)': 死しに損そこなう = 'narrowly escape death.' This idiomatic 'nearly' use is fixed to a small set of verbs.

Jengo shows 〜損なう the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.

Sources Compiled from published Japanese grammar references.