use·ful 
/ˈju:sfəl/ adjective
/ˈju:sfəl/ adjective [more useful; most useful] : helping to do or achieve something
▪ a useful invention/tool/skill ▪ Does anyone have any useful suggestions/advice? ▪ It can be useful to know CPR. ▪ The Internet is useful for finding information quickly. ▪ The therapy is useful as a treatment for diabetes. = The therapy is useful in treating diabetes. ▪ She has become one of the team's most useful players. ▪ Why don't you do something useful with your life? ▪ The data could prove (to be) useful [=people may eventually find that the data is helpful] in identifying future problems. ▪ I found this information (to be) quite useful. ▪ Her pocketknife came in useful [=(more commonly) came in handy] when we needed to cut the tangled fishing line. ▪ I tried to make myself useful [=to be helpful; to do something helpful] by organizing his closet for him. ▪ the useful life of a satellite [=the amount of time during which a satellite is in good enough condition to be used]
▪ a useful invention/tool/skill ▪ Does anyone have any useful suggestions/advice? ▪ It can be useful to know CPR. ▪ The Internet is useful for finding information quickly. ▪ The therapy is useful as a treatment for diabetes. = The therapy is useful in treating diabetes. ▪ She has become one of the team's most useful players. ▪ Why don't you do something useful with your life? ▪ The data could prove (to be) useful [=people may eventually find that the data is helpful] in identifying future problems. ▪ I found this information (to be) quite useful. ▪ Her pocketknife came in useful [=(more commonly) came in handy] when we needed to cut the tangled fishing line. ▪ I tried to make myself useful [=to be helpful; to do something helpful] by organizing his closet for him. ▪ the useful life of a satellite [=the amount of time during which a satellite is in good enough condition to be used]
— use·ful·ly adverb
▪ The lessons learned from that experience can be usefully applied to the current situation. ▪ She kept herself usefully employed.
▪ The lessons learned from that experience can be usefully applied to the current situation. ▪ She kept herself usefully employed.
— use·ful·ness noun [noncount]
▪ He questioned the usefulness of such a device.
▪ He questioned the usefulness of such a device.
