noun

a person or thing that reduces a shock or that forms a barrier between incompatible or antagonistic people or things.

family and friends can provide a buffer against stress

cushion,bulwark,shield,screen,barrier,guard,safeguard,hedge,shock absorber,armour,intermediary,middleman,go-between

verb

lessen or moderate the impact of (something).

the massage helped to buffer the strain

cushion,absorb,soften,lessen,diminish,moderate,mitigate,allay,deaden,muffle,stifle,shield