zesílitget*/become*/grow* stronger, increase (in strength)
zesílenýstrengthened, reinforced, increased, turned up
zešíletgo* crazy/insane, lose* mind, go* mad/nuts
strong: make sth strongerzesílit, posílit co
become: The wind became stronger.Vítr zesílil.
zesílit: Vítr ještě zesílil.The wind became even stronger.
zesílit: Zesil to rádio.Turn the radio up.