Who is Tookish in The Hobbit?

There is no one called 'Tookish'. 'Took' is a Hobbit family/clan name, a clan known for being more adventurous than others. To be called 'Tookish' it generally means that a Hobbit is descended from Tooks (ie, Bilbo Baggins, from his mother Belladonna Took) and feeling the call of adventure.