The term 'pick at' can be defined by three words: NAG (3 letters), PESTER (6 letters), and CARP (4 letters). NAG is a verb meaning to annoy or irritate someone with persistent fault-finding, complaints, or demands. PESTER is a verb meaning to bother or annoy someone with persistent and often petty requests or criticism. CARP is a verb meaning to find fault or complain querulously or unreasonably. All three words are related to the idea of finding fault or complaining in an annoying or irritating way.