floccinaucinihilipilification
Concise Oxford English Dictionary © 2008 Oxford University Press:
floccinaucinihilipilification /ˌflɒksɪˌnɔːsɪˌnɪhɪlɪˌpɪlɪfɪˈkeɪʃ(ə)n/
▶noun rare the action or habit of estimating something as worthless.
'floccinaucinihilipilification' also found in these Oxford entries:

