гру́бо

fairly common #4164C2adverbadverb of гру́бый

1.
rudely, harshly, curtly
Он гру́бо отве́тил матери.
He answered his mother rudely.
Most common sense: about how someone speaks or treats others.
2.
roughly, coarsely, crudely
Доски́ были гру́бо обтёсаны.
The boards were roughly hewn.
About the way something is made, cut or handled.
3.
roughly, approximately
Гру́бо говоря, э́то стоит ты́сячу рубле́й.
Roughly speaking, it costs a thousand roubles.
Mainly in the phrase 'грубо говоря' (roughly speaking).

Examples

Э́то так грубо.
That's so rude.
Грубо шути́ть над свои́м нача́льником на лю́дях.
It's rude to make fun of your boss in public.
Эта коробящая фраза прозвучала очень грубо.
That cringeworthy phrase sounded very rude.
Буркнутое им слово прозвучало грубо.
The word he muttered sounded rude.
Грубо говоря, сезо́ны в А́нглии совпада́ют с япо́нскими.
Roughly speaking, the seasons in England correspond with those in Japan.
Слово "укр" звучит грубо, лучше его не использовать.
The word “укр” sounds rude; it is better not to use it.
Том на нас грубо прикри́кнул.
Tom shouted at us in a gruff voice.
Я сожале́ю, что вела́ себя с ним грубо.
I regret having been rude to him.