Get characters before first space

Or just sub, with credit to @flodel:

sub(" .*", "", words)
# and if the 'space' can also be a tab or other white-space:
sub("\\s.*","",words)
#[1] "the"    "brown"  "lazier"

You can use qdap's beg2char (beginning of the string to a particular character) as follows:

x <- c("the quick", "brown dogs were", "lazier than quick foxes")
library(qdap)
beg2char(x)
## [1] "the"    "brown"  "lazier"