考かんがえあぐねる

ichidan verb, transitive verb

be at a loss after much thought; rack one's brains in vain; think and think but get nowhere

Describes the state of having thought hard about something but being unable to reach a conclusion or find a solution. Often implies frustration or mental exhaustion.

• 何なん度ども考かんがえあぐねた末すえ、結けっ局きょくあきらめた。

  After racking my brains over and over, I finally gave up.

• 彼かれはその問もん題だいについて考かんがえあぐねている。

  He is at a loss over that problem.