watertight：不透水的，防水的；严密的，无懈可击的 

词根词缀：water水 + -tight紧的→密不透…的

• stalk
• stalker
• stalking
• stall
• stallholder
• stallion
• stalwart
• stamen
• stamina
• stammer
• stamp
• stampede
• stance
• stanch
• stanchion
• stand
• standard
• standard
• standard-bearer
• standardisation
• standardise
• standardization
• standardize
• standing
• standoff