-ably

(Latin: suffix; able manner, capably)

Forming adverbs corresponding to adjectives in -able.

unimpeachably
1. Difficult or impossible to impeach: "The witness testified unimpeachably during the trial."
2. Beyond reproach; blameless: "They behaved unimpeachably during the trip."
3. Beyond doubt; unquestionable: "She produced unimpeachably many works of greatness."
unjustifiable (adjective)
1. Impossible to excuse, to pardon, or to justify; not justifiable.
2. Incapable of being justified or explained.
unmovably
unpalatable, unpalatability, unpalatably
1. Not pleasant, agreeable, or acceptable to the taste or mind; for example, "We had an unpalatable meal at that restaurant."
2. Not tasting good: having an unpleasant taste.
3. Disagreeable or unacceptable; obnoxious: "I can not tolerate his unpalatable behavior."
unprofitably
unquestionably (adverb), more unquestionably, most unquestionably
In a manner that leaves no room for doubt or uncertainty; indisputable: Mr. Deal, the principal of the school, spoke in an unquestionably firm voice when he told the playground bully that he would be permanently expelled from the school unless he behaved himself.
unreasonably
unreliably
1. In an unfaithful, undependable, or unreliable manner.
2. Characterized by not being reliable or not to be relied or depended on.
unseasonably (adverb), more unseasonably, most unseasonably
Not at the most suitable time: The weather where Tom lives is unseasonably cold while where his brother lives is unseasonably warm.
unserviceably
unsociably
1. In an unsociable manner.
2. Not congenial; incompatible.
unstable (adjective); more unstable, most unstable
1. Referring to something or someone that is inclined to change abruptly: The weather was totally unstable that day because the sun was shining one minute, and in the next minute, dark clouds suddenly appeared and it rained!
2. Concerning an item or an object which is infirm or tottery: The camping table was very unstable so Jim had to put a flat piece of wood under one leg to level it.
3. Characteristic of a person whose emotions or behavior are unpredictable: James was very difficult to get along with because his comportment and conduct were totally unstable.
valuably
variably (adverb), more variably, most variably
venerably