rash meaning
EN
[ræʃ] [-æʃ] 
US WRash
- A rash is a change of the skin which affects its color, appearance, or texture.
- A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell, and may be painful.
- The causes, and therefore treatments for rashes, vary widely. Diagnosis must take into account such things as the appearance of the rash, other symptoms, what the patient may have been exposed to, occupation, and occurrence in family members.
EN Rash 
- NounPLrashes
- VerbSGrashesPRrashingPT, PPrashed
- AdjectiveCOMrasherSUPrashest
- More Examples
- Used in the Middle of Sentence
- Kalinic later saw red for a rash tackle on Paul Scharner before Gabriel Tamas was dismissed for bringing down Diouf.
- Used in the Ending of Sentence
- HZ as a subsequent reactivation, more seldom as a result of reinfection, of VZV presents as a clinical syndrome characterized by a unilateral radicular pain and avesicular, distributed cutaneous rash.
- Eating strawberries always brings me out in a rash.
- Used in the Middle of Sentence
Definition of rash in English Dictionary
- Part-of-Speech Hierarchy
- Adjectives
- Nouns
- Countable nouns
- Singularia tantum
- Uncountable nouns
- Uncountable nouns
- Countable nouns
- Verbs
- Adjectives
Source: Wiktionary
Grammatically, this word "rash" is an adjective. It's also a noun, more specifically, a countable noun and a singularia tantum. It's also a verb.