A person who has an allergy.
"The allergic child immediately sneezed when her mother opened a bag of peanuts."
In plain English: An allergic person is someone who has an immune system reaction to something that usually doesn't hurt other people.
"The doctor asked about his allergic to peanuts before giving him the medication."
having an allergy or peculiar or excessive susceptibility (especially to a specific factor)
"allergic children"
"hypersensitive to pollen"
Of or pertaining to allergy.
"The patient's symptoms were clearly allergic in nature, triggered by exposure to pollen."
In plain English: Allergic means your body has an unwanted reaction to something harmless, like food or pollen.
"My mom is allergic to peanuts, so she never brings them when we go out for dinner."
The word allergic comes from combining the noun allergy with the suffix -ic to form an adjective describing a state of hypersensitivity. This construction was first used in English around 1905 to describe reactions to specific substances like pollen or food.