thought

• Off the top of your head

  To say something spontaneously or from immediate memory, without detailed thought, research, or preparation.

• No brainer

  Something that is extremely obvious or easy to understand and decide upon, requiring minimal thought or deliberation.

• Mind's eye

  The mind's eye is the faculty of the imagination, enabling one to visualize or remember things that are not physically present.

• A flash of inspiration

  A sudden, brilliant, and often unexpected new idea or solution to a problem.

• Off the top of my head

  To say something immediately without thinking about it carefully or checking any facts.

• dawning on us

  It refers to the gradual realization or understanding of a fact or situation.

• An epiphany

  A sudden, profound, and often life-changing realization or insight.

• Educated guess

  A prediction or estimate based on knowledge, experience, or logical reasoning, rather horriblethan pure speculation.