Formal or polite alternative for "f***ing around" [closed]

I want to tell my uncle that I am "f***ing around" but I certainly can't use the F (f*ck) word.

If you don't want to say 'f*ck' then say fiddle instead. Both 'fck' and 'fiddle' start with F, so 'fck' can easily be replaced by 'fiddle'.

Fiddle around: To spend time doing small things that are not important or necessary — Cambridge English dictionary

You could substitute 'fiddle' for 'f*ck'.

Example: Uncle, I'm fiddling around. (It does not sound vulgar).

Single word for that would be loafing.

Loaf (verb): Spend one's time in an aimless, idle way.

— Lexico

Example: Uncle, I'm loafing.

Or footle. But as others have said, it's unlikely to be understood.

Footle (verb): Engage in fruitless activity; mess about.

— Lexico

You say:

I am wasting my time doing silly things and I want a phrase or word for that.

I would use messing around:

[Merriam-Webster]
1 : to waste time : DAWDLE, IDLE
2 a : ASSOCIATE
         // didn't mess around with gangs
2 b : FLIRT, PHILANDER

Not only does it have the same verbal form as f—ing around, but it also conveys many of the same senses.

In short, it can be easily substituted in most sentences:

I was just messing around in my room.

The word mess can also be substituted for f— in many cases:

"Don't mess with me!"