ついうっかり

A compound adverb combining つい (unintentionally, before one realizes) and うっかり (carelessly, absentmindedly). The two words reinforce each other to describe a momentary lapse. Very natural and common in spoken Japanese.

Usage

Almost always followed by てしまう (or its casual form ちゃう), since the action is unintentional and often regrettable. Both つい and うっかり can be used independently with similar meanings, but the combination is more emphatic.

Common collocations

• ついうっかり忘(わす)れる — to carelessly forget
• ついうっかり言(い)ってしまう — to accidentally say something
• ついうっかり寝(ね)てしまう — to fall asleep without meaning to
• ついうっかり間違(まちが)える — to make a careless mistake

Similar words

• つい — unintentionally; milder, can also imply yielding to temptation
• うっかり — carelessly; focuses on inattention
• 思(おも)わず — involuntarily; implies a reflexive or instinctive action