Subsetting dataframe by changes in values by a threshold from one column to another

General
2

Your description is not completely clear to me, is this what you mean?

library(dplyr)

sample_df <- data.frame(
           x = c(1, 2, 4, 5, 6),
           y = c(2, 3, 4, 4, 6)
)

sample_df %>% 
    filter(abs(y - x) >= 1)
#>   x y
#> 1 1 2
#> 2 2 3
#> 3 5 4

Created on 2020-01-17 by the reprex package (v0.3.0.9000)

if not, please provide a proper REPRoducible EXample (reprex) illustrating your issue.