МЫСЛЬ _|_ THINK / MYSL [mɨslʲ] 

Hint with an alternative definition: it is like a mind’s slip (a small piece of paper) with a picture (on a virtual mini-easel), feelings or lay of words in sleep & reality (muse); it can be easily created (no need of paints)

Hint with composition: when the mind is ill it has many thoughts / imagine a mystic isle of premise hidden in clouds with a huge mussel and a pearl inside / master-musing of mind with thoughts / myth or miss + lie = thought is often false, or thought is a miss or a seal (realized or a dream) / muesli of words / tough thought is like a slam & missile (US) / thought is a muscle of thinking / your head is a missal (a book containing the prayers and chants)

Russian pro-tip: мир + мы + слово = мысль / мысли – мы слышим всё

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Вымыселover-vim + мысль = hyperbole (too much to be true) virtual invention

МЫШЛЕНИЕ _|_ THINKING / MYSHLENIYE [mɨˈʂlʲenʲɪɪ̯ə] 

Hint: it is like the system of mesh-lens in your brain = thinking / imagine Michelin tires spinning in your head with sparks and smoke

FALSE + LAUGH: мышь (mouse) or мышление = to avoid confusion imagine a mighty mouse running in a maze of thinking / мыс (beak-head, cape, cusp) or мысль = the thought is a beak-head too, imagine the cloud over the head / bonus: mull = мыс > мысль, imagine the mull in the form of thinking head

Mental visualization: M (convolutions of the brain) + Ы (the tongue, like a voiced thought) + СЛ(hands, action from thought)