Literally "preparedness": the technical command — speed, clarity, stamina, evenness — that lets a player execute whatever the music asks without visible effort. Praise for tayari says the hands are fully trained; it deliberately says nothing about taste.
The tradition treats it as necessary but insufficient. A player with tayari and no ideas is a machine; ideas without tayari stay hypothetical. It is built through slow-to-fast cycling of material in daily practice and maintained like fitness — it decays measurably when the work lapses.