ПОКОЙ _|_ TRANQUILITY / POKOY [pɐˈkoɪ̯]
Hint with an alternative definition: It is the state of being perfectly calm with a composure (or it is a similar situation or environment). Imagine a placid & opaque place in a park with the absence of red sparks, sharp spikes, noise (plonks), and any disturbance.
Hint with composition: poise, pause + coy / up + quite or quite port is a decoy (often) / pocket + noise = quiet and calm
Hints with translation + consonant words (by sounds or letters): peace & calm is your cope / slowpoke boy is always calm or perfect yoga practitioner / post-coital phase = calm / the end point of calm is a post-apocalypse
Hints with a mirror: your cop guards your “покой”
Mental visualization: ПО (a person creeps to …) + КОЙ (…a large hammock — K is the corner of the hammock, O is the pillow, Й is the other corner of the hammock and a tree branch)