Change one letter ONLY,

[TrixxxTrixxx]

Mumm (champagne)

 

[K9k77]

Mump

 

[greenpen13]

Rump

 

[CritterFunatic]

How did Ovum turn into Mumm? That's multiple changed letters, not just one.

Anyway:

Prom

 

[Knutshack]

How did Ovum turn into Mumm? That's multiple changed letters, not just one.

Anyway:

Prom

I usually search up words and I could not find anything other than business companies acronyms that one was really difficult

Prop

 

[voutinen]

I usually search up words and I could not find anything other than business companies acronyms that one was really difficult

Prop

Prep

 

[TrixxxTrixxx]

I usually search up words and I could not find anything other than business companies acronyms that one was really difficult

Prop

How did Ovum turn into Mumm? That's multiple changed letters, not just one.

Anyway:

Prom

Argh you are right, my humble apologies . I was having such a hard time with Ovum.

 

[Knutshack]

Argh you are right, my humble apologies . I was having such a hard time with Ovum.

You're not alone, that was a DIFFICULT one!
Pred (Prednisone)

 

[K9D]

Dreg

 

[thil28]

Dreg

Grid

 

[K9D]

Drip

 

[thil28]

Drip

Ripe

 

[K9D]

Rope

 

[thil28]

Pear

 

[K9D]

Rear

 

[thil28]

Roar

 

[K9D]

Rawr

 

[thil28]

Wrap

 

[K9D]

Pray

 

[thil28]

Prey

 

[K9D]

Year

 

[thil28]

Yard

 

[K9D]

Drag

 

[thil28]

Drug

 

[Freespiritman]

Grudge

 

[CritterFunatic]

You're not alone, that was a DIFFICULT one!
Pred (Prednisone)

Agreed, that's why I, as a non native speaker didn't even want to touch that one. Couldn't find anything either.

Grudge

I'm pretty certain you aren't supposed to tack on additional letters, going by the fact that this game started as a four letter word and after 1247 pages still is a four letter word.

Skipping it and following up from "Drug":

Drum

 

[Knutshack]

Murr

 

[fourstance]

Rump

 

[thil28]

Pump

 

[CritterFunatic]

Dump