Throbbing is the present participle of throb, and still a verb. It doesn't qualify the noun, so it isn't an adjective. Nor can you have an adjective with the suffix -ing.VeluCherry said:to throb - to produce a strong, regular beat = verbNezumiiroKitsune said:Throbbing is a verb.
throbbing is the adjective
Also one of my favourite words. Oh snap that makes me sound slutty