切(き)れないBeing unable to finish or complete

These two expressions are opposite in meaning. 切る conveys resolution or the complete execution of an action, e.g. やり切る 'do it all the way' or 使い切る 'use up'. 切れない is its antonym, used to express not being able to see an action through to the end, e.g. 食べ切れない ('I can't finish eating it.').

These phrases are opposites—one expresses a completed action, the other, incompleteness. 上がる・上げる is typically used when the action results in a finished product, e.g. '論文を書き上げる' ('finish writing a thesis'). 切れない expresses the inability to finish something fully, e.g. '食べ切れなかった' ('I couldn't finish eating it').

てしまう・ちゃう and 切れない can express opposite meanings. One nuance of てしまう・ちゃう is to do something completely, e.g. 食べてしまった has one potential meaning of 'I ate it all.'. In contrast, 食べ切れなかった would mean 'I couldn't eat all of it.'. Note that てしまう・ちゃう can also express regret or an unintentional action, which 切れない does not. For example, 食べてしまった could also mean 'I ate it (even though I didn't intend to).'.

Both 切れない and かねる express inability to do something, but differ in tone and nuance. 切れない describes physical or practical inability to complete an action, e.g. '食べ切れない' ('I can't finish eating it'). かねる conveys emotional or psychological reluctance and often appears in formal or polite refusals, e.g. '分かりかねます' ('I'm afraid I don't know').

Both 切れない and 得ない describe types of impossibility, but with different focuses. 切れない emphasizes physical or circumstantial inability to complete an action, e.g. '読み切れなかった' ('I couldn't finish reading it'). In contrast, 得ない expresses abstract or conceptual impossibility, e.g. '起こり得ない' ('impossible to happen'), and is used for events that cannot realistically occur.