Synonyms of heads up

Noun

1. heads-up, warning

usage: a warning message; "he sent a heads-up to the District Attorney"

Verb

1. head, head up, be

usage: be the first or leading member of (a group) and excel; "This student heads the class"

Adjective

1. heads-up, wide-awake, alert (vs. unalert), watchful

usage: fully alert and watchful; "played heads-up ball"