If a combatant is surprised by combat starting, that combatant has Disadvantage on their Initiative roll. For example, if an ambusher starts combat while hidden from a foe who is unaware that combat is starting, that foe is surprised.
If a combatant is surprised by combat starting, that combatant has Disadvantage on their Initiative roll. For example, if an ambusher starts combat while hidden from a foe who is unaware that combat is starting, that foe is surprised.