Similar words: regrettable, regret, regretful, regress, segregate, egregious, segregated, regressive. Meaning: [rɪ'gretəblɪ] 
adv. by bad luck.
adv. by bad luck. 61. He was regrettably drunk.
62. Regrettably, the illuminating ideas in The Economist are often obscured by stilted prose.
63. Unfortunately, I have another engagement for that evening, so regrettably I must decline.
64. But, he says regrettably it will not be very many.
More similar words: regrettable, regret, regretful, regress, segregate, egregious, segregated, regressive, regression, segregation, desegregate, regressive tax, notably, comfortably, irritably, hospitably, inevitably, lamentably, indubitably, ineluctably, uncomfortably, indisputably, irretrievably, retractable, vendetta, regroup, dilettante, degree, egress, foreground.