1.
febrile; caused by or accompanied by fever
A medical term used before another noun to mean that a condition arises from or comes with a fever. It appears almost only in compounds, most commonly 熱性けいれん (febrile convulsion).
From 熱 (fever, heat) + 性 (nature, -ic). Note the small っ: the reading is ねっせい, not ねつせい.
Common collocations
Usage
A bound form: it does not stand alone as a subject or object, and it is not used with な or の. Outside medicine it is rare, so learners will meet it mainly at a clinic or in health information for parents.