1. To trouble greatly; to harass or plague.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• investm,
• infent,
• mainfest,
• infeld,
• reinfest,
• infrot,
• offest,
• unlest,
• inist,
• incert,
• incast,
• invet,
• insyst,
• insest,
• inlist,
• infot,
• inteset,
• infus,
• investd,
• manfest

• infested,
• infers,
• infect,
• infected,
• invest,
• invested,
• invective,
• in focus,
• infection,
• infective,
• investing,
• in fact,
• investor,
• invests.

The adverb form of "infest" is "infestingly".

The adjective form of the word "infest" is "infested".

The plural form of the word "infest" is "infests"

The singular form of the word "infest" remains the same, which is "infest".