1goof 
/ˈgu:f/ verb
goofs; goofed; goof·ing /ˈgu:f/ verb chiefly US, informal : to make a careless or stupid mistake : to make a goof [no obj] ▪ It was clear that someone had goofed. — often + up ▪ I really goofed up this time. [+ obj] — usually + up ▪ They both goofed up their lines.
goof around
[phrasal verb] chiefly US, informal : to spend time doing silly or playful things
▪ The kids are goofing around, watching TV and hanging out.
▪ The kids are goofing around, watching TV and hanging out.
goof off
[phrasal verb] chiefly US, informal : to spend time doing things that are not useful or serious
▪ He spent the day goofing off instead of working. — see also goof-off
▪ He spent the day goofing off instead of working. — see also goof-off
goof on [phrasal verb]
goof on (someone or something) US slang : to make jokes about (someone or something) in a way that is either playful or unkind
▪ They're just goofing on [=kidding with, teasing] you.
▪ They're just goofing on [=kidding with, teasing] you.
