System Reference Document 5.2.1
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Deafened [Condition]
While you have the Deafened condition, you experi -
ence the following effect.
 Can’t Hear. You can’t hear and automatically fail 
any ability check that requires hearing.
Death Saving Throw
A player character must make a Death Saving 
Throw (also called a Death Save) if they start their 
turn with 0 Hit Points. See also  “Playing the Game” 
(“Damage and Healing”).
Dehydration [Hazard]
A creature requires an amount of water per day 
based on its size, as shown in the Water Needs per 
Day table. A creature that drinks less than half the 
required water for a day gains 1 Exhaustion level 
at the day’s end. Exhaustion caused by dehydra-
tion can’t be removed until the creature drinks the 
full amount of water required for a day. See also  
“Exhaustion.”
Water Needs per Day
Size Water
Tiny 1/4 gallon
Small 1 gallon
Medium 1 gallon
Size Water
Large 4 gallons
Huge 16 gallons
Gargantuan 64 gallons
Difficult Terrain
If a space is Difficult Terrain, every foot of move -
ment in that space costs 1 extra foot. For example, 
moving 5 feet through Difficult Terrain costs 10 feet 
of movement. Difficult Terrain isn’t cumulative; ei -
ther a space is Difficult Terrain or it isn’t.
 A space is Difficult Terrain if the space contains 
any of the following or something similar:
• A creature that isn’t Tiny or your ally
• Furniture that is sized for creatures of your size or 
larger
• Heavy snow, ice, rubble, or undergrowth
• Liquid that’s between shin- and waist-deep
• A narrow opening sized for a creature one size 
smaller than you
• A slope of 20 degrees or more
Difficulty Class
A Difficulty Class (DC) is the target number for an 
ability check or a saving throw. See also  “Playing the 
Game” (“D20 Tests”).
Dim Light
An area with Dim Light is Lightly Obscured. See 
also “Lightly Obscured” and “Playing the Game” 
(“Exploration”).
Disadvantage
If you have Disadvantage on a D20 Test, roll two 
d20s and use the lower roll. A roll can’t be affected 
by more than one Disadvantage, and Advantage and 
Disadvantage on the same roll cancel each other. See 
also “Playing the Game” (“D20 Tests”).
Disengage [Action]
If you take the Disengage action, your movement 
doesn’t provoke Opportunity Attacks for the rest of 
the current turn.
Dodge [Action]
If you take the Dodge action, you gain the following 
benefits: until the start of your next turn, any attack 
roll made against you has Disadvantage if you can 
see the attacker, and you make Dexterity saving 
throws with Advantage.
 You lose these benefits if you have the Incapaci -
tated condition or if your Speed is 0.
Emanation [Area of Effect]
An Emanation is an area of effect that extends in 
straight lines from a creature or an object in all di -
rections. The effect that creates an Emanation spec -
ifies the distance it extends.
 An Emanation moves with the creature or object 
that is its origin unless it is an instantaneous or a 
stationary effect.
 An Emanation’s origin (creature or object) isn’t 
included in the area of effect unless its creator de -
cides otherwise.
Encounter
An encounter is a scene in an adventure that is part 
of at least one of the game’s three pillars: social in -
teraction, exploration, or combat. See also  “Playing 
the Game” (“Social Interaction,” “Exploration,” and 
“Combat”).
Enemy
A creature is your enemy if it fights against you in 
combat, actively works to harm you, or is desig -
nated as your enemy by the rules or GM.
Exhaustion [Condition]
While you have the Exhaustion condition, you 
experience the following effects.
 Exhaustion Levels. This condition is cumulative. 
Each time you receive it, you gain 1 Exhaustion 
level. You die if your Exhaustion level is 6.
 D20 Tests Affected. When you make a D20 Test, 
the roll is reduced by 2 times your Exhaustion level.
 Speed Reduced. Your Speed is reduced by a num-
ber of feet equal to 5 times your Exhaustion level.
 Removing Exhaustion Levels. Finishing a Long 
Rest removes 1 of your Exhaustion levels. When 
your Exhaustion level reaches 0, the condition ends.