"You're a socialist" is a pejorative used universally by conservatives. Therefore by your definition, it's not an economic term, it's a pejorative.
Now, if you insist that it is indeed an economic term because it describes an approach to economics, fair enough. Just like trickle down.
To be clear: "trickle down"
is a pejorative term applied to supply-side economics. It is pejorative in as much as it highlights, and is intended to highlight, the negative view of the policies as being beneficial to the rich with
only a trickle (or "leak", as it was once described in the 19th century) reaching the lower classes - i.e. that the policies disproportionately aid the already well-off, albeit with the overall aim of raising standards for all.
Because the metaphor is aimed at the perceived negative aspect of such supply-side policies, the term
is pejorative. However, it is a term that seems more increasingly to simply be used synonymously with "supply-side", with no intended pejorative intent, which is unfortunate as it only serves to give people who don't really know any better a somewhat jaundiced view of the actual policies.
Sure, some policies (supply-side or otherwise) may be genuinely set up to be "trickle-down": the UK dropped the £60k p.a. maximum contribution one could make to one's pension pot because they thought highly-paid doctors were retiring early as a result of current policies... this change, imo, was clearly a policy disproportionately aimed at the already-wealthy with the aim of the benefit "trickling down" to the masses (through the doctors remaining in work). And it hasn't really worked to do anything other than benefit those doctors who weren't retiring early anyway.
This makes "trickle down" being pejorative distinct from simply using an existing term as pejorative, such as "socialist", which has an original non-pejorative usage and has gained a pejorative usage due to, among other things, association with the more extreme elements thereof.
Now, does supply-side economics work? That's a question, indeed.
