A worrier is a person who worries a lot — not once, about one thing, but as a habit, as part of who they are. That habitual sense is the whole point of the word. You would not call someone a worrier because they are worried about tomorrow's exam; you call them a worrier because they are worried about something every day. It is usually said gently, even fondly, most often about family: 'my mother's a terrible worrier', 'he's always been a worrier'. It can carry mild criticism — you worry too much, calm down — but it is much softer than 'worrywart', which is openly teasing. There is a very common fixed phrase, 'a born worrier', meaning someone who has been like this all their life and cannot help it. Formed from worry + -er, the ending that turns a verb into the person who does it. Note the spelling: worry ends in -y after a consonant, so the y changes to i before the ending — worry → worrier, exactly like carry → carrier.

愛操心的人、容易緊張的人。台灣說「他很會想」「愛操煩的個性」。語氣通常是親切帶點無奈，不是罵人。