someone acting like a fool or silly and childish or saying something foolish or silly and childish immature. can be used harshly or in a soft humorous endearisg way also someone who looks odd or extremely strange.
origan Australian colloquialism
harsh form ....george was drunk the other day and was acting like a real tosspot
soft form......as if about a child. He was running around with a bucket on their head looking like a tosspot