sharp-eyed lookout

Translations
осторожный наблюдатель
The sharp-eyed lookout spotted the approaching ship long before anyone else.
Осторожный наблюдатель заметил приближающийся корабль задолго до остальных.
Definitions
A person who is very observant and attentive, especially when watching for something specific or keeping watch for danger or important events.
Words
sharp

adjective
зоркий
eyed

adjective
глазастый
lookout

noun
наблюдатель