ex-cubō buī, bitum, āre, to lie out of doors, camp out: in agro.

— To lie out on guard, keep watch, watch: pro castris, Cs.: ad mare, Cs.: per muros, V.: excubitum in portas cohortīs mittere, S.: (Cupido Chiae) Pulchris excubat in genis, lurks, H.

—Fig., to watch, be watchful, be vigilant, be on the alert: ad opus, Cs.: in navibus, Cs.: animo: pro aliquo.