gnaw (v.)
- ablate
- abrade
- abrase
- afflict
- agonize
- ail
- annoy
- badger
- bark
- bedevil
- beleaguer
- bite
- bother
- burn
- canker
- chafe
- champ
- chaw
- chew
- chomp
- consume
- convulse
- corrode
- crucify
- crumble
- cut
- devour
- distress
- eat
- erase
- erode
- excruciate
- fester
- file
- fray
- frazzle
- fret
- gall
- gnash
- grate
- graze
- grind
- gripe
- gum
- harass
- harrow
- harry
- haunt
- hector
- hurt
- inflame
- irk
- irritate
- lacerate
- martyr
- martyrize
- masticate
- mouth
- mumble
- munch
- nag
- nettle
- nibble
- nip
- oxidize
- pain
- peeve
- pester
- pierce
- pinch
- plague
- prick
- rack
- rankle
- rasp
- raze
- rub
- ruminate
- rust
- scour
- scrape
- scrub
- scuff
- skin
- stab
- sting
- tease
- torment
- torture
- trouble
- tweak
- twist
- vex
- wear
- worry
- wound
- wring