1) Dawdler 2) Drone 3) Foot-dragger 4) Idler 5) Laggard 6) Lagger 7) Late arrival 8) Lazybones 9) One bringing up the rear 10) One out of line 11) Sailor absent for 73 hours 12) Shirker 13) Slacker 14) Slowcoach 15) Strayer 16) Trailer 1) Laggard 2) Strayer 
In a convoy, a ship that is unable to maintain speed and falls behind.
• (n.) A roving vagabond. • (n.) Something that stands alone or by itself. • (n.) Something that shoots, or spreads out, beyond the rest, or too far; an exuberant growth. • (n.) One who straggles, or departs from the direct or proper course, or from the company to which he belongs; one who falls behind the rest; one who rambles ...
Strag'gler noun 1. One who straggles, or departs from the direct or proper course, or from the company to which he belongs; one who falls behind the rest; one who rambles without any settled direction. 2. A roving vagabond. Shak. 3. Something that shoots, or spreads out...
[n] - someone who strays or falls behind
strayer noun someone who strays or falls behind