flatline

verb

flat·​line ˈflat-ˌlīn 

flatlined; flatlining; flatlines

intransitive verb

1

a

: to register on an electronic monitor as having no brain waves or heartbeat

b

: die

2

a

: to be in a state of no progress or advancement

b

: to come to an end

flatliner noun

Synonyms

• check out
• conk (out)
• croak [slang]
• decease
• demise
• depart
• die
• drop
• end
• exit
• expire
• fall
• go
• kick in [slang]
• kick off [slang]
• part
• pass (on)
• pass away
• peg out [chiefly British]
• perish
• pop off
• step out
• succumb

Examples of flatline in a Sentence

the patient was fading fast, and doctors expected him to flatline before the night was over

Recent Examples on the Web

But after flatlining for nearly two decades, the Nikkei 225 Index quadrupled in value from 2009 to 2024. —Michael Useem, Fortune Asia, 24 Oct. 2024

Economic growth has been tepid so far this year, coming in at 0.2% in August after flatlining in June and July. —Jenni Reid, CNBC, 22 Oct. 2024

Productivity growth in the U.K. has flatlined since the financial crisis and has now been reset to levels of growth not seen since the 1850s, a new report published by the Institute of Fiscal Studies and Citi highlighted. —Shawn Tully, Fortune Europe, 10 Oct. 2024

Automakers across the board are losing millions — some are losing billions — as customer demand appears to have flatlined after an initial burst of excitement. —Andrew J. Hawkins, The Verge, 1 Sep. 2024

Word History

First Known Use

1980, in the meaning defined at sense 1a

Medical Definition

flatline

intransitive verb

flat·​line ˈflat-ˌlīn 

flatlined; flatlining

1

: to register on an electronic monitor as having no heartbeat or brain waves : to experience cessation of heart contractions or brain wave activity as indicated by a flat line on a electrocardiogram or electroencephalogram

I flatlined on the operating table, but Dr. Bunsom managed to revive me.

—Alison Wright, Yoga Journal

He used to be ill quite a bit as a younger child, and his heart flatlined four times before he was 6.

—Ginnie Graham, Tulsa World

2

: die entry 1

But just because death is expected doesn't mean it's any less depressing when the patient finally flatlines.

—Phil Taylor, Sports Illustrated