good
The prisoner was released early for good conduct.

discreditable (BrE), disgraceful, immoral, improper, inappropriate, unethical, ungentlemanly (BrE), unprofessional, unseemly (esp. BrE)
aggressive (esp. BrE), violent
criminal, disorderly, fraudulent (law, esp. BrE), illegal, negligent, unlawful, wrongful
He was arrested for disorderly conduct.

unsporting (BrE), unsportsmanlike (esp. AmE)
homosexual, sexual
personal
business, professional
The business conduct of this bank will be subject to UK rules.
Our organization sets high standards of professional conduct.

police
human, moral
It is tempting to think of morality as a guide to human conduct.

engage in
The committee concluded that the senators had engaged in improper conduct.

govern, regulate
rules governing police conduct

explain
The police chief was asked to explain his conduct.

conduct by
The violent conduct by the strikers was condemned.

conduct towards/toward
her conduct towards/toward her husband

a code of conduct, rules of conduct, standards of conduct

proper
The elders were responsible for the proper conduct of community life.

day-to-day
the day-to-day conduct of the business of the company

independently, separately
Education was conducted separately for males and females.

jointly, simultaneously
a survey conducted jointly by two teams of researchers

personally
properly
successfully
regularly, routinely
We regularly conduct safety inspections.

online
Today, 50% of opinion polls are conducted online.

honourably/honorably, well, with dignity
She conducts herself with great dignity.

as
He always conducted himself as a gentleman.

in
They have conducted themselves in a very professional manner.

well
a substance which conducts electricity well

Conduct is used with these nouns as the subject:
researcher

Conduct is used with these nouns as the object:
activity, affair, analysis, assault, assessment, auction, autopsy, band, blitz, business, campaign, census, ceremony, check, choir, class, concerto, current, defence, demonstration, diplomacy, election, electricity, enquiry, espionage, evaluation, examination, excavation, exercise, experiment, fieldwork, funeral, hearing, heat, inquest, inspection, interrogation, interview, inventory, investigation, litigation, manoeuvre, meeting, mission, negotiation, operation, orchestra, patrol, poll, post-mortem, premiere, procedure, programme, raid, reconnaissance, referendum, registration, rehearsal, research, review, ritual, search, seminar, simulation, study, surveillance, survey, symphony, talk, test, tour, trade, transaction, trial, vendetta, visit, warfare, wedding, work, workshop, worship