4 letters

bool ∙ Cool ∙ dool ∙ fool ∙ gool ∙ hool mool ∙ pool ∙ rool sool ∙ tool ∙ wool ∙ zool

5 letters

acool dhool jhool Shool ∙ skool ∙ snool ∙ spool ∙ brool ∙ crool ∙ drool ∙ stool ∙

6 letters

babool ∙ recool alcool ∙ Uncool ∙ befool ∙ refool unfool ∙ kagool ∙ school ∙ alkool calool simool jarool ∙ retool ∙ dewool ∙

7 letters

babbool jambool ∙ subcool ∙ precool ∙ prefool damfool ∙ tomfool ∙ outfool ∙ arghool bathool Kurnool subpool vanpool ∙ carpool ∙ respool ∙ unspool ∙ destool enstool kittool nonwool ∙

8 letters

forecool overcool ∙ unbefool archfool deschool ∙ reschool ∙ unschool Linalool ∙ Tidepool fishpool antipool millpool Moonpool Lanspool earspool cesspool ∙ sesspool ∙ Formtool Barstool ∙ Longwool Rockwool

9 letters

ultracool ∙ undercool ∙ supercool ∙ subschool preschool ∙ nonschool ∙ proschool Blackpool whirlpool ∙ liverpool Pontypool toadstool ∙ fridstool faldstool ∙ foldstool frogstool backstool cuckstool stepstool ∙ campstool ∙ Footstool ∙ underwool ∙ lambswool bullswool

10 letters

warrambool homeschool ∙ foreschool highschool minischool ∙ antischool postschool playschool ∙ Hartlepool freedstool closestool ∙ frithstool ∙ birthstool nightstool

11 letters

Warrnambool intraschool extraschool underschool superschool ∙ afterschool interschool ∙ bishopstool

12 letters

paddockstool

Words with a ∙ are valid Scrabble words (SOWPODS word list)