1. To be
worried or scared about something, frequently used to describe a drug-induced state of
paranoia.
2. To vomit.
Origin: Great
Grimsby. Possibly originally evolved from the word 'defecate', via 'shitting it'.
1. 'I'm deffing', 'She's deffin'-out', 'I deffed-out', 'Deff-out'
2. 'I
just deffed'. 'He's deffin''.