(US, idiomatic) After reconsidering; on further consideration.

(idiomatic) To change one's opinion, or be uneasy about a previous decision.

(physics, philosophy) An attempt to solve a problem using the power of human imagination.

Marked by or showing lack of due thought or care; careless. / Inconsiderate, inattentive. / Lacking thought or consideration.

In a thoughtful or pensive manner. / In a way that shows kindness or consideration for others.

Demonstrating thought or careful consideration. / Demonstrating kindness or consideration for others.

plural of thought

Thoughtful and considerate attention. / Careful deliberation before action.

disregard for other's feelings / heedless disregard for the consequences of one's actions

(UK) Alternative form of on second thought