to be more important or significant by comparison

For years he overshadowed his brother.

to cast a shadow over; cover with shadows, clouds, darkness, etc.; darken or obscure

clouds overshadowing the moon.

to make sad or hang heavily over; cast a pall on

a disappointment that overshadowed their last years.

Archaic . to shelter or protect.

verb

adumbrate , becloud , bedim , cloud , command , darken , dim , dominate , dwarf , eclipse , excel , govern , haze , leave in the shade , obfuscate , outshine , outweigh , overcast , overcloud , overweigh , preponderate , rise above , rule , shadow , steal spotlight , surpass , take precedence , tower above , veil , befog , blear , blur , dull , fog , gloom , mist , cover , obscure , reduce , shade