This is the 999th most frequent Hungarian word.
orvos
Doctor (medical professional).
Here, 'orvos' is used as a noun meaning 'doctor' referring to a person in the medical profession.
Az orvos megvizsgálta a beteget.
The doctor examined the patient.
In this sentence, 'orvosi' is the adjective form of 'orvos', meaning 'medical' and describing the type of assistance.
Orvosi segítségre van szüksége.
They need medical assistance.
Here, 'orvos' is used as a noun again, meaning 'doctor', referring to a profession someone aspires to.