Synonyms
Thought: concept, cogitation, consideration, deliberation, estimation, idea, imagination, reflection, consideration, speculation, supposition.
Think: ponder; muse; cogitate, deliberate, esteem, imagine, reason, reflect, seriously consider; speculate, suppose.
Are you having deep thoughts today? I’m playing in the shallow end of the thought pool.
Nothing underfoot at the deep end except “serious consideration”.
Keep your head above water (-;