Conventional means following the usual accepted way. Nothing surprising, and nothing wrong with it either.
The word is neutral on the surface and faintly damning underneath: describing a wedding, a suit or an opinion as conventional suggests safety rather than imagination. It also does hard technical work, where conventional means non-nuclear in talk of weapons, and non-organic in farming. The noun convention is what everyone has agreed to do without ever voting on it. Unconventional, the opposite, is nearly always meant as a compliment.
1adjectiveconventionalFollowing what is usual and generally accepted.
“They took a conventional approach and it worked.”
2adjectiveordinaryOf the ordinary kind, as opposed to nuclear or organic.
“The country reduced its conventional forces.”
Proto-Indo-European
*gʷem-
Latin
conventiō — meeting, assembling; agreement, convention
Middle French
convention
English
convention
English, today
conventional
Built from
From convention + -al. convention Recorded since about 1440, borrowed from Middle French convention, from Latin conventiō (“meeting, assembling; agreement, convention”), from conveniō (“come, gather or meet together, assemble”), from con- (“with, together”) + veniō (“come”). Equivalent to convene + tion.
Etymology from Wiktionary, CC BY-SA