tight-lipped

[ tahyt-lipt ]

/ ˈtaɪtˈlɪpt /

speaking very little; taciturn; close-mouthed.

having the lips drawn tight.

Origin of tight-lipped

First recorded in 1875–80

The actress is tight-lipped about the final season of ‘Mad Men.’

Is Elisabeth Moss the One 'True Detective' Loves? She Doesn't Deny It. |Melissa Leon |August 12, 2014 |DAILY BEAST
I chased a tight-lipped Thain as he scurried through the lobby to get back to his headquarters.

Banks Really Are Different Five Years After the Financial Crisis |Daniel Gross |September 17, 2013 |DAILY BEAST
Traditionally, the FAA has been tight-lipped about its relations with airplane manufacturers during accident investigations.

Aviation’s Iron Lady: NTSB Chairwoman Deborah Hersman |Clive Irving |January 28, 2013 |DAILY BEAST
Her protagonists are tight-lipped and their worlds are sharply-observed.

This Week’s Hot Reads: November 6, 2012 |Mythili Rao |November 7, 2012 |DAILY BEAST

But on the question of how he was identified and tracked, the officials were tight-lipped.

America’s Secret Libya War |John Barry |August 30, 2011 |DAILY BEAST
A close-fisted, tight-lipped Mormon—a skinflint if I ever saw one!

The Rainbow Trail |Zane Grey
Tight-lipped, using her flashlight, she ran through the kitchen.

The White Moll |Frank L. Packard
Dave grinned, tight-lipped, eased back on the stick and lifted the One-Ten clear of the ground and upward toward the dawn sky.

Dave Dawson with the R.A.F |R. Sidney Bowen
"As sure as it's necessary to be," the Intelligence officer replied, tight-lipped.

Dave Dawson at Casablanca |Robert Sydney Bowen
Horace they knew only as a very slim, tight-lipped, and immature-looking young man, who waited every night to take her home.

Flappers and Philosophers |F. Scott Fitzgerald

tight-lipped

reticent, secretive, or taciturn

with the lips pressed tightly together, as through anger