epistasis /i-pisˈtə-sis/

1. The suppression by a gene of another non-allelomorphic gene
2. The arrest of a discharge or secretion
3. A scum which forms on the surface of a liquid, esp urine

• what ails him at
• what an idea
• what an if
• what are you doing with
• what a vengeance
• what cheer
• what do you know
• what do you say to
• what-d'you-call-'em
• what-d'you-call-it
• whate'er
• what else
• whaten
• whatever
• whatevs
• what for
• what for a
• what gives
• what have you
• what ho
• what if
• what is he for a man
• what-like
• Whatman paper
• what matter if