What is the meaning of 'grandiloquence' and 'frigidy' in longinus' on the sublime?

also briefly get some notion of HORACE's The Art of Poetry. sometimes questions are also asked on HORACE, not as a poet, but as a literary critic

to understand sublime well also read Edmund Burke "Of the Sublime"

Longinus explores the elememt of sublimity in writing and states that five sources can lead to this goal: great thoughts, noble diction, dignified word arrangement strong emotions ...