expression, noun
bad cold
A common phrase for a severe cold, often used when symptoms are strong or prolonged.
ひどい風邪をひいて、一週間も寝込んだ。
I caught a bad cold and was bedridden for a whole week.
彼はひどい風邪で声が出ない。
He has a bad cold and can't speak.
Compound of ひどい (severe) and 風邪 (cold). The phrase is transparent and follows standard adjective-noun modification.