Halliday & Matthiessen (2014: 160):
We should distinguish from Expletives the individual lexical items (‘swear words’) that may be sprinkled anywhere throughout the discourse and have no grammatical function in the clause (as with bloody in it’s a bloody taxation bloody policy, God).
Cf Halliday (1994: 85):
Note that individual lexical items expressing the speaker’s attitude, when incorporated into the structure of a group (usually a nominal group, like bloody in those bloody mosquitoes), have no grammatical function in the clause.