rea‧son‧a‧bly S2 W3 /ˈriːzənəbli/ adverb
[Word Family: noun: reason, reasoning, reasonableness; adjective: reasonable ≠ unreasonable, reasoned; verb: reason; adverb: reasonably ≠ unreasonably]

1. [+ adjective/adverb] quite or to a satisfactory degree, but not completely:
The car is in reasonably good condition.
He’s doing reasonably well at school.

2. in a way that is right or fair:
He can’t reasonably be expected to have known that.

3. in a sensible way:
Despite her anger, she had behaved very reasonably.

[TahlilGaran] Dictionary of Contemporary English ▲

rather/quite especially British English more than a little, but less than very. British people often use these words before adjectives in conversation. In many cases they do not intend to change the meaning – it is just something that people say:
She seemed rather unhappy.
It's rather a difficult question.
It’s getting quite late.
Malaria is rather common in this area.
fairly rather. Fairly is used in both British and American English:
The test was fairly easy.
It’s a fairly long way to the next town.
pretty spoken rather. Pretty is more informal than the other words and is used in spoken English:
Her French is pretty good.
We’re in a pretty strong position.
reasonably to a satisfactory level or degree:
He plays reasonably well.
Let's just say that I am reasonably confident we'll win.
moderately formal more than a little, but not very:
Her family was moderately wealthy.
The food was moderately good, but not as good as the food in the other restaurants.
Use a moderately high heat.
a moderately difficult climb
somewhat formal fairly or to a small degree. Somewhat is used especially when talking about the size or degree of something. It is often used in comparatives:
The celebrations were somewhat larger than last year’s.
He looked somewhat irritated.
a somewhat surprising decision

[TahlilGaran] English Thesaurus ▲