[ hahrd-on, -awn ]
/ ˈhɑrdˌɒn, -ˌɔn /
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noun, plural hard-ons.Slang: Vulgar.
an erection of the penis.
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Origin of hard-on

First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does hard-on mean?

A hard-on is slang for an erection of the penis. It has been extended as a metaphor for being excited about something in general.

The vulgar slang hard-on is not to be confused with the expression to be hard (on someone) is to be mean and critical, or to he expression to go hard (on something), meaning “to go all out.”

What are some other forms of hard-on?

hard on

Where does hard-on come from?

To be hard (on someone), or “to be tough on or critical of,” has also been around since at least the 1860s. Hard, here, implies unfeeling treatment. In the 1950s, hard-on was slang for “tough” or “aggressive” behavior.

Hard on for “sexually aroused” is evidenced in 1893, as in He was hard on for her. By 1922, the word had become a noun for “erection” (e.g., He had a hard-on). Erect penises are characterized—if you need us to spell it out—as hard.

By the 1990s–2000s, hard-on had extended (no pun intended) to intense excitement in nonsexual contexts (e.g., You have a hard-on for McRib sandwiches).

How is hard-on used in real life?

As a noun, a hard-on is slang for “erection”—and not something you want to go around saying in a polite setting.

Verb phrases involving hard on vary in meaning. It often appears in to be hard (on someone), though in British English to be hard (on someone), as a cop on a thief, can mean “on the heels of.”

To go hard (on something) is Black slang for “going all out,” or “being really into” it, whether it’s sports or burritos.


More examples of hard-on:

“To me, ‘being hard on yourself’ — it’s just another way of saying ‘having passion for the game.’ It’s just another way of saying ‘high expectations.’”

—Ryan Howard, The Players’ Tribune, September 2018

How to use hard-on in a sentence

Other Idioms and Phrases with hard-on

hard on


Also, hard upon, hard by. In close proximity, as in The police were hard on the heels of the thieves, or It was hard upon three o'clock, or Their house is hard by ours. The variants are used less than hard on. [Second half of 1700s]


be hard on. Deal severely with, cause damage to. For example, He asked the teacher not to be too hard on those who forgot the assignment, or That cat has really been hard on the upholstery. [Second half of 1600s] Also see hard time, def. 2.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.