For an outfit that's super straightforward but can be manipulated in a variety of different ways, marry a navy crew-neck sweater with dark green chinos. If you want to feel a bit classier now, complement this ensemble with beige suede loafers. This one is a nice pick when it comes to an easy-to-transition outfit. When it comes to dressing ideas for 40-year-old gents, this ensemble is a good look on almost any gent.