heffalump /ˈhɛfəlʌmp/noun 3forms 2phrases 1 noun3 •(humorous) (A child's name for) an elephant.We went to the zoo and saw some heffalumps. •(slang, offensive) A clumsy or overweight person.'What are you, thumping around like fucking heffalumps? The twins are trying to get to sleep,' he says, staring at us on the bed. — 2014 •(informal, figurative) Something that is elusive.In fact, some researchers are skeptical about the feasibility of constructing such an index and describe it as a "search for [a] heffalump" [...] or looking for a "Holy Grail" [...]. — 2009 formsHeffalumps · heffalumps Phrases with heffalump heffalump trapA situation where an attempt to trap or outwit someone ends up backfiring on the original schemer.