
1) Advisory notice 2) Alert 3) Chairs 4) Final stage of a tournament 5) Style of play 6) Warning 7) Warning shout 8) Warning words
Found on
https://www.crosswordclues.com/clue/heads-up

Wilshire Boulevard eastbound in Westwood, Los Angeles, California, as seen on July 5, 2004. Photographed and uploaded by user Coolcaesar. ...
Found on
http://en.wikipedia.org/wiki/Heads-up
[Bassnectar EP] Heads Up is an EP by American electronic music artist Bassnectar, released November 4, 2008 on Amorphous Music. The title track, `Heads Up`, was originally a song to be seen on an upcoming full length titled The Other Side but never came to fruition, as Cozza Frenzy was released shortly after. `Lucy In The Sky With Diamonds ...
Found on
http://en.wikipedia.org/wiki/Heads_Up_(Bassnectar_EP)
[Death from Above 1979 EP] Heads Up is Toronto duo Death from Above 1979`s debut recording, a six song EP released by Vancouver label Ache Records on December 15, 2002. It was later re-issued because of the success of their first full-length album, You`re a Woman, I`m a Machine. The original press run was 1004 copies; 200 on clear and the r...
Found on
http://en.wikipedia.org/wiki/Heads_Up_(Death_from_Above_1979_EP)

This refers to a situation where only two players remain in contention for the pot, as in one-on-one.
Found on
http://www.encyclo.co.uk/local/20611

A pot that is being contested by only two players. Example: 'It was heads-up by the turn.'
Found on
http://www.encyclo.co.uk/local/21171

When there are only two players at the table, they are said to be playing heads-up. "Johnny and I got heads-up after Tim lost with his pair of jacks to my pocket queens." A hand where everyone has folded except for two people is sometimes called a "heads-up pot". "I suspected Johnny was attempting to steal the blinds, so I three-bet him, hoping to ...
Found on
http://www.encyclo.co.uk/local/21206

Heads-up is poker slang for a game with just two players.
Found on
http://www.probertencyclopaedia.com/browse/ZH.HTM

[
adj] - fully alert and watchful
Found on
http://www.webdictionary.co.uk/definition.php?query=heads-up
wide-awake adjective fully alert and watchful; `played heads-up ball`
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.