Solicitousness is the quality of caring a lot about whether someone is safe, well, or comfortable — and showing it. A person with solicitousness keeps asking if you are cold, if you have eaten, if you need to sit down. It is the noun for the adjective 'solicitous'. Two things are worth knowing. First, this is a rare and rather heavy word; 'solicitude' (the next word) is the one educated speakers usually reach for, and in everyday talk people just say 'concern' or 'kindness'. If you write 'solicitousness' in an essay it will not be wrong, only unusual. Second, the word is often used with a small doubt inside it. Because solicitous care is care you can SEE, writers use it when someone is being a bit too attentive — fussing over you, or being extra nice to a customer or a boss because they want something. So it can be warm (a nurse's solicitousness) or slightly cool (the waiter's solicitousness made her uneasy). The sentence around it tells you which. It is almost always uncountable: you have solicitousness, not 'a solicitousness'.

殷勤關切；無微不至的關心（帶有「關心得很明顯、有時過了頭」的味道；中性偏書面，日常口語會說「很關心」「很體貼」）