Underhanding

Maybe during the first session we can try to size up the type of anger problem she has: exploding? underhanding? somatizing?

Source: wiktionary

In holier ways that honor and bless with peace and happiness, passing the understanding of ghost whisperers 'tall', under-handing utterances of -- disquieting anxieties, invading love's sanctuary.

Source: wiktionary

The third passive type of anger is called underhanding. It's the least obvious type but nevertheless very destructive and harmful. It involves using sarcasm, gossip, teasing, sharing secrets, pouting, or obstructive acts such as forgetting to give someone a message or sabotaging group efforts.

Source: wiktionary