Adolescence /ˌæd

chronic /ˈkrɒn.ɪk/ /ˈkrɑː.nɪk/ adjective LONG LASTING
1. (especially of a disease or something bad) continuing for a long time
chronic diseases/conditions
chronic arthritis/pain
a chronic invalid
There is a chronic shortage of teachers.
chronic /ˈkrɒn.ɪk/ /ˈkrɑː.nɪk/ adjective BAD
2. UK informal very bad
The acting was chronic.
harmful /ˈhɑːm.f ə l/ /ˈhɑːrm-/ adjective
causing harm
This group of chemicals is known to be harmful to people with asthma.
healthy /ˈhel.θi/ adjective HEALTH
1. strong and well
She's a normal healthy child.
He looks healthy enough.
2. showing that you are strong and well
The walk had given her a healthy glow.
a healthy appetite
3. good for your health
a healthy diet
a good healthy walk
infectious /ɪnˈfek.ʃəs/ adjective
1. able to pass a disease from one person, animal or plant to another
an infectious disease/patient
2. describes something that has an effect on everyone who is present and makes them want to join in
an infectious laugh
infectious enthusiasm