Go-slow endless in grotesque style (6)
I believe the answer is:
gothic
'style' is the definition.
(I have seen 'Architectural style ' mean 'gothic' so perhaps 'style' could also mean 'gothic')
'go-slow endless in grotesque' is the wordplay.
I cannot quite see how this works, but
'go' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for gothic that I've seen before include "Style of architecture, literatureand film" , "Style of architecture common in Europe in 12th-16th centuries" , "Early style of architecture and a literature dealing with mysterious events in eerie settings" , "Style of architecture popular in Europe in the 12th to 16th centuries" , "Style of architecture and gloomy books" .)