"without regard," 1570s, from heed (n.) + -less. Related: Heedlessly; heedlessness. Spenser has heedlesshood.
Entries linking to heedless
heed n.
"careful attention, notice, regard," early 14c., from heed (v.). Survives only in literary use, in compounds, and as the object of verbs (take heed, etc.).
-less
word-forming element meaning "lacking, cannot be, does not," from Old English -leas, from leas "free (from), devoid (of), false, feigned," from Proto-Germanic *lausaz (cognates: Dutch -loos, German -los "-less," Old Norse lauss "loose, free, vacant, dissolute," Middle Dutch los, German los "loose, free," Gothic laus "empty, vain"), from PIE root *leu- "to loosen, divide, cut apart." Related to loose and lease.