dplyr / tidy way to filter a vector based on a substring?

We can see some good examples of how to filter a data.frame based on a substring; is there a tidy way of doing this for a vector? (that is, without using grepl() or similar)

Example

I tried what would work on a data.frame

# Leave only words that don't begin with 'cat'

vec <- c("cat", "catamaran", "dog", "mouse", "catacombs")

vec %>% filter(substr(1, 3) != "cat") # %>% ... etc

but

Error in UseMethod("filter_") : 
  no applicable method for 'filter_' applied to an object of class "character"

Note

We could use something like vec %>% { .[!grepl("cat", .)] }, or more accurately vec %>% { .[substr(., 1, 3) != "cat"]}, but I will try to find something that..

1. is more beginner friendly, with more verbally descriptive functions (e.g. a complete novice can probably guess what 'filter' does but possibly not 'grepl')
2. has less finicky syntax (as few { and } as possible)
3. pipes more elegantly (e.g. vec %>% filter(...) %>% next operations)
4. contains as little repetition as possible, noting that the grepl way uses the original vector (denoted by .) twice (as opposed to just once which would be ideal)