Successful means having reached what you aimed for. A successful business, a successful application, she was successful at the second attempt.
It takes in for a field and at for an activity: successful in business, successful at persuading people. Applied to a person alone, successful nearly always means financially successful, which is worth noticing. Note the spelling, which has two c's and two s's in the middle and one l at the end — a word people get wrong for their whole lives — and that the adverb successfully is one of the most common words in a covering letter.
1adjectivesuccessfulHaving achieved what was aimed for.
“The appeal was successful and the fine was cancelled.”
synonyms: triumphant, effective
2adjectivewealthHaving achieved wealth or a high position.
“He is successful and does not look it.”
Too few real examples of this word to estimate which sense is commonest.
successful is a state of having achieved.
Latin
successus
English
success
English, today
successful
Built from
From success + ful. success Learned borrowing from Latin successus. Latin successus, from succēdō (“succeed”), from sub- (“next to”) + cēdō (“go, move”).
Etymology from Wiktionary, CC BY-SA