Thoughtful means somebody thought about you. The friend who turns up with the exact biscuits you mentioned once, or texts on the morning of your hospital appointment.
The word has a quieter second life, closer to its parts: a thoughtful face is one lost in thinking, and a thoughtful answer or a thoughtful book is careful and considered rather than quick. So a thoughtful pause and a thoughtful present have almost nothing to do with each other — the first is thinking, the second is kindness. That's thoughtful of you is the standard reply to a small kindness. The adverb is thoughtfully and the noun is thoughtfulness. The opposite, thoughtless, lands harder than it looks: it accuses you of not caring, not of failing to think.
1adjectiveconsiderateKind; paying attention to what other people need or feel.~14%
“It was thoughtful of her to save him a seat at the front.”
synonyms: considerate, kind
2adjectivethoughtfulQuiet and serious because you are thinking about something.~29%
“He went thoughtful for a moment and stared out at the rain.”
3adjectiveconsideredCarefully worked out; showing serious thinking.~57%
“She wrote a thoughtful reply instead of the angry one she wanted to send.”
synonyms: considered, reflective
Shares are an estimate: a language model read 7 sentences found in the wild and placed 7 of them on a sense — a count of our sample, not a measurement of English.
Also accepted in games: considerate
Thoughtful is Middle English thoȝtful, and it is exactly what it looks like: thought plus -ful, full of thought. Swedish built the same word, tankfull, out of its own pieces. English then kept both halves of that literal sense — full of thought about a problem, and full of thought about a person.
Middle English
thoȝtful
English, today
thoughtful
From Middle English thoȝtful, thohtful, equivalent to thought + ful. Compare Dutch gedachtenvol, Swedish tankfull.
Etymology from Wiktionary, CC BY-SA