Amphetamine and Hard drug

Amphetamine noun - A central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression.

Hard drug and amphetamine are semantically related. In some cases you can use "Hard drug" instead a noun "Amphetamine".

Hard drug noun - A narcotic that is considered relatively strong and likely to cause addiction.

Amphetamine and hard drug are semantically related. Sometimes you can replace term "Amphetamine" with "Hard drug", this terms are similar.