noun which may take the genitive case particle 'no'
overheated; hyper-; overearnest
Describes a state of being excessively heated, enthusiastic, or intense, often with a nuance of being slightly too much. Used for both literal overheating and figurative overexcitement.
The discussion is getting a bit overheated.
This computer is running a little hot, so let's give it a rest.
過熱 is a noun/suru-verb meaning 'overheating' or 'superheating', while 過熱気味 adds the suffix 気味 to indicate a tendency or slight state of being overheated.
気味 is a suffix meaning '-like' or 'tending to', often used to express a slight degree of something, as in 疲れ気味 (a bit tired).
Compound of 過熱 (overheat) and 気味 (tendency, slight feeling). The exact historical derivation is uncertain, but the word is a straightforward combination of these elements.