Grouser

2 clues
One who complains
Constant complainer
Similar answers:
Aboutacropgrower
Aboveground
Abovegroundpool
Abstruser
Abuser
Abusers
Accuser
Accusers
Actorsgroup
Adhocgroup
Afewgrouchymen
Agegroup
Aggro
Agro
Agroan
Agron
Agronom
Agronomic
Agronomist
Agronomy